diff --git a/app/build.gradle b/app/build.gradle
index 1141d8232..50299afc5 100644
--- a/app/build.gradle
+++ b/app/build.gradle
@@ -9,7 +9,7 @@ android {
 
     defaultConfig {
         applicationId "com.simplemobiletools.gallery"
-        minSdkVersion 16
+        minSdkVersion 21
         targetSdkVersion 28
         versionCode 201
         versionName "4.6.5"
@@ -43,7 +43,7 @@ android {
 }
 
 dependencies {
-    implementation 'com.simplemobiletools:commons:4.9.1'
+    implementation 'com.simplemobiletools:commons:5.1.2'
     implementation 'com.theartofdev.edmodo:android-image-cropper:2.7.0'
     implementation 'androidx.multidex:multidex:2.0.0'
     implementation 'it.sephiroth.android.exif:library:1.0.1'
@@ -65,7 +65,7 @@ dependencies {
     implementation 'com.github.tibbi:subsampling-scale-image-view:v3.10.1-fork'
 
     // implementation 'com.github.chrisbanes:PhotoView:2.1.4'
-    implementation 'com.github.tibbi:PhotoView:2.1.4-fork'
+    implementation 'com.github.tibbi:PhotoView:2.2.0-fork'
 }
 
 Properties props = new Properties()
diff --git a/app/src/main/kotlin/com/simplemobiletools/gallery/activities/MainActivity.kt b/app/src/main/kotlin/com/simplemobiletools/gallery/activities/MainActivity.kt
index 4590512cb..ce4c12e27 100644
--- a/app/src/main/kotlin/com/simplemobiletools/gallery/activities/MainActivity.kt
+++ b/app/src/main/kotlin/com/simplemobiletools/gallery/activities/MainActivity.kt
@@ -12,7 +12,6 @@ import android.view.MenuItem
 import android.view.ViewGroup
 import android.widget.FrameLayout
 import android.widget.Toast
-import androidx.recyclerview.widget.GridLayoutManager
 import androidx.recyclerview.widget.RecyclerView
 import com.simplemobiletools.commons.dialogs.CreateNewFolderDialog
 import com.simplemobiletools.commons.dialogs.FilePickerDialog
@@ -966,7 +965,7 @@ class MainActivity : SimpleActivity(), DirectoryOperationsListener {
     }
 
     private fun checkLastMediaChanged() {
-        if (isActivityDestroyed()) {
+        if (isDestroyed) {
             return
         }
 
diff --git a/app/src/main/kotlin/com/simplemobiletools/gallery/activities/MediaActivity.kt b/app/src/main/kotlin/com/simplemobiletools/gallery/activities/MediaActivity.kt
index 1dd2514b6..0d37b2013 100644
--- a/app/src/main/kotlin/com/simplemobiletools/gallery/activities/MediaActivity.kt
+++ b/app/src/main/kotlin/com/simplemobiletools/gallery/activities/MediaActivity.kt
@@ -398,7 +398,7 @@ class MediaActivity : SimpleActivity(), MediaOperationsListener {
     }
 
     private fun checkLastMediaChanged() {
-        if (isActivityDestroyed()) {
+        if (isDestroyed) {
             return
         }
 
diff --git a/app/src/main/kotlin/com/simplemobiletools/gallery/activities/PanoramaActivity.kt b/app/src/main/kotlin/com/simplemobiletools/gallery/activities/PanoramaActivity.kt
index e1131e92f..e13f4e055 100644
--- a/app/src/main/kotlin/com/simplemobiletools/gallery/activities/PanoramaActivity.kt
+++ b/app/src/main/kotlin/com/simplemobiletools/gallery/activities/PanoramaActivity.kt
@@ -1,11 +1,9 @@
 package com.simplemobiletools.gallery.activities
 
-import android.annotation.TargetApi
 import android.content.res.Configuration
 import android.graphics.Bitmap
 import android.graphics.BitmapFactory
 import android.graphics.Color
-import android.os.Build
 import android.os.Bundle
 import android.view.View
 import android.view.Window
@@ -17,7 +15,6 @@ import com.simplemobiletools.commons.extensions.beVisible
 import com.simplemobiletools.commons.extensions.showErrorToast
 import com.simplemobiletools.commons.extensions.toast
 import com.simplemobiletools.commons.helpers.PERMISSION_WRITE_STORAGE
-import com.simplemobiletools.commons.helpers.isLollipopPlus
 import com.simplemobiletools.commons.helpers.isPiePlus
 import com.simplemobiletools.gallery.R
 import com.simplemobiletools.gallery.extensions.*
@@ -65,7 +62,6 @@ open class PanoramaActivity : SimpleActivity() {
         }
     }
 
-    @TargetApi(Build.VERSION_CODES.LOLLIPOP)
     override fun onResume() {
         super.onResume()
         panorama_view.resumeRendering()
@@ -74,9 +70,7 @@ open class PanoramaActivity : SimpleActivity() {
             updateStatusbarColor(Color.BLACK)
         }
 
-        if (isLollipopPlus()) {
-            window.statusBarColor = resources.getColor(R.color.circle_black_background)
-        }
+        window.statusBarColor = resources.getColor(R.color.circle_black_background)
     }
 
     override fun onPause() {
diff --git a/app/src/main/kotlin/com/simplemobiletools/gallery/activities/SetWallpaperActivity.kt b/app/src/main/kotlin/com/simplemobiletools/gallery/activities/SetWallpaperActivity.kt
index 5f02df853..8fd8dcfb5 100644
--- a/app/src/main/kotlin/com/simplemobiletools/gallery/activities/SetWallpaperActivity.kt
+++ b/app/src/main/kotlin/com/simplemobiletools/gallery/activities/SetWallpaperActivity.kt
@@ -10,7 +10,6 @@ import android.os.Bundle
 import android.view.Menu
 import android.view.MenuItem
 import com.simplemobiletools.commons.dialogs.RadioGroupDialog
-import com.simplemobiletools.commons.extensions.isActivityDestroyed
 import com.simplemobiletools.commons.extensions.toast
 import com.simplemobiletools.commons.helpers.isNougatPlus
 import com.simplemobiletools.commons.models.RadioItem
@@ -113,7 +112,7 @@ class SetWallpaperActivity : SimpleActivity(), CropImageView.OnCropImageComplete
 
     @SuppressLint("NewApi")
     override fun onCropImageComplete(view: CropImageView?, result: CropImageView.CropResult) {
-        if (isActivityDestroyed())
+        if (isDestroyed)
             return
 
         if (result.error == null) {
diff --git a/app/src/main/kotlin/com/simplemobiletools/gallery/activities/ViewPagerActivity.kt b/app/src/main/kotlin/com/simplemobiletools/gallery/activities/ViewPagerActivity.kt
index 9a318db83..03cd4a0fa 100644
--- a/app/src/main/kotlin/com/simplemobiletools/gallery/activities/ViewPagerActivity.kt
+++ b/app/src/main/kotlin/com/simplemobiletools/gallery/activities/ViewPagerActivity.kt
@@ -2,7 +2,6 @@ package com.simplemobiletools.gallery.activities
 
 import android.animation.Animator
 import android.animation.ValueAnimator
-import android.annotation.SuppressLint
 import android.annotation.TargetApi
 import android.app.Activity
 import android.content.Intent
@@ -20,13 +19,13 @@ import android.os.Build
 import android.os.Bundle
 import android.os.Handler
 import android.provider.MediaStore
-import androidx.viewpager.widget.ViewPager
 import android.util.DisplayMetrics
 import android.view.Menu
 import android.view.MenuItem
 import android.view.View
 import android.view.WindowManager
 import android.view.animation.DecelerateInterpolator
+import androidx.viewpager.widget.ViewPager
 import com.bumptech.glide.Glide
 import com.simplemobiletools.commons.dialogs.PropertiesDialog
 import com.simplemobiletools.commons.dialogs.RenameItemDialog
@@ -103,7 +102,6 @@ class ViewPagerActivity : SimpleActivity(), ViewPager.OnPageChangeListener, View
         initFavorites()
     }
 
-    @TargetApi(Build.VERSION_CODES.LOLLIPOP)
     override fun onResume() {
         super.onResume()
         if (!hasPermission(PERMISSION_WRITE_STORAGE)) {
@@ -112,9 +110,7 @@ class ViewPagerActivity : SimpleActivity(), ViewPager.OnPageChangeListener, View
         }
 
         if (config.bottomActions) {
-            if (isLollipopPlus()) {
-                window.navigationBarColor = Color.TRANSPARENT
-            }
+            window.navigationBarColor = Color.TRANSPARENT
         } else {
             setTranslucentNavigation()
         }
@@ -135,9 +131,7 @@ class ViewPagerActivity : SimpleActivity(), ViewPager.OnPageChangeListener, View
         }
 
         supportActionBar?.setBackgroundDrawable(ColorDrawable(Color.TRANSPARENT))
-        if (isLollipopPlus()) {
-            window.statusBarColor = Color.TRANSPARENT
-        }
+        window.statusBarColor = Color.TRANSPARENT
     }
 
     override fun onPause() {
@@ -225,7 +219,7 @@ class ViewPagerActivity : SimpleActivity(), ViewPager.OnPageChangeListener, View
         supportActionBar?.title = mPath.getFilenameFromPath()
 
         view_pager.onGlobalLayout {
-            if (!isActivityDestroyed()) {
+            if (!isDestroyed) {
                 if (mMediaFiles.isNotEmpty()) {
                     gotMedia(mMediaFiles as ArrayList<ThumbnailItem>)
                 }
@@ -365,7 +359,7 @@ class ViewPagerActivity : SimpleActivity(), ViewPager.OnPageChangeListener, View
 
     private fun updatePagerItems(media: MutableList<Medium>) {
         val pagerAdapter = MyPagerAdapter(this, supportFragmentManager, media)
-        if (!isActivityDestroyed()) {
+        if (!isDestroyed) {
             view_pager.apply {
                 adapter = pagerAdapter
                 currentItem = mPos
@@ -384,7 +378,7 @@ class ViewPagerActivity : SimpleActivity(), ViewPager.OnPageChangeListener, View
     private fun startSlideshow() {
         if (getMediaForSlideshow()) {
             view_pager.onGlobalLayout {
-                if (!isActivityDestroyed()) {
+                if (!isDestroyed) {
                     hideSystemUI(true)
                     mSlideshowInterval = config.slideshowInterval
                     mSlideshowMoveBackwards = config.slideshowMoveBackwards
@@ -474,7 +468,7 @@ class ViewPagerActivity : SimpleActivity(), ViewPager.OnPageChangeListener, View
         if (mIsSlideshowActive) {
             if (getCurrentMedium()!!.isImage() || getCurrentMedium()!!.isGIF()) {
                 mSlideshowHandler.postDelayed({
-                    if (mIsSlideshowActive && !isActivityDestroyed()) {
+                    if (mIsSlideshowActive && !isDestroyed) {
                         swipeToNextMedium()
                     }
                 }, mSlideshowInterval * 1000L)
@@ -980,18 +974,11 @@ class ViewPagerActivity : SimpleActivity(), ViewPager.OnPageChangeListener, View
         initBottomActionsLayout()
     }
 
-    @SuppressLint("NewApi")
     private fun measureScreen() {
         val metrics = DisplayMetrics()
-        if (isJellyBean1Plus()) {
-            windowManager.defaultDisplay.getRealMetrics(metrics)
-            screenWidth = metrics.widthPixels
-            screenHeight = metrics.heightPixels
-        } else {
-            windowManager.defaultDisplay.getMetrics(metrics)
-            screenWidth = metrics.widthPixels
-            screenHeight = metrics.heightPixels
-        }
+        windowManager.defaultDisplay.getRealMetrics(metrics)
+        screenWidth = metrics.widthPixels
+        screenHeight = metrics.heightPixels
     }
 
     private fun refreshViewPager() {
diff --git a/app/src/main/kotlin/com/simplemobiletools/gallery/adapters/DirectoryAdapter.kt b/app/src/main/kotlin/com/simplemobiletools/gallery/adapters/DirectoryAdapter.kt
index 12b095d18..f03a9e92c 100644
--- a/app/src/main/kotlin/com/simplemobiletools/gallery/adapters/DirectoryAdapter.kt
+++ b/app/src/main/kotlin/com/simplemobiletools/gallery/adapters/DirectoryAdapter.kt
@@ -1,6 +1,5 @@
 package com.simplemobiletools.gallery.adapters
 
-import android.util.SparseArray
 import android.view.Menu
 import android.view.View
 import android.view.ViewGroup
@@ -26,8 +25,6 @@ import com.simplemobiletools.gallery.models.AlbumCover
 import com.simplemobiletools.gallery.models.Directory
 import kotlinx.android.synthetic.main.directory_item_list.view.*
 import java.io.File
-import java.util.*
-import kotlin.collections.ArrayList
 
 class DirectoryAdapter(activity: BaseSimpleActivity, var dirs: ArrayList<Directory>, val listener: DirectoryOperationsListener?, recyclerView: MyRecyclerView,
                        val isPickIntent: Boolean, fastScroller: FastScroller? = null, itemClick: (Any) -> Unit) :
@@ -48,14 +45,6 @@ class DirectoryAdapter(activity: BaseSimpleActivity, var dirs: ArrayList<Directo
 
     override fun getActionMenuId() = R.menu.cab_directories
 
-    override fun prepareItemSelection(viewHolder: ViewHolder) {
-        viewHolder.itemView.dir_check?.background?.applyColorFilter(primaryColor)
-    }
-
-    override fun markViewHolderSelection(select: Boolean, viewHolder: ViewHolder?) {
-        viewHolder?.itemView?.dir_check?.beVisibleIf(select)
-    }
-
     override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): ViewHolder {
         val layoutType = if (isListViewType) R.layout.directory_item_list else R.layout.directory_item_grid
         return createViewHolder(layoutType, parent)
@@ -63,10 +52,10 @@ class DirectoryAdapter(activity: BaseSimpleActivity, var dirs: ArrayList<Directo
 
     override fun onBindViewHolder(holder: MyRecyclerViewAdapter.ViewHolder, position: Int) {
         val dir = dirs.getOrNull(position) ?: return
-        val view = holder.bindView(dir, true, !isPickIntent) { itemView, adapterPosition ->
+        holder.bindView(dir, true, !isPickIntent) { itemView, adapterPosition ->
             setupView(itemView, dir)
         }
-        bindViewHolder(holder, position, view)
+        bindViewHolder(holder)
     }
 
     override fun getItemCount() = dirs.size
@@ -90,7 +79,7 @@ class DirectoryAdapter(activity: BaseSimpleActivity, var dirs: ArrayList<Directo
     }
 
     override fun actionItemPressed(id: Int) {
-        if (selectedPositions.isEmpty()) {
+        if (selectedKeys.isEmpty()) {
             return
         }
 
@@ -117,17 +106,21 @@ class DirectoryAdapter(activity: BaseSimpleActivity, var dirs: ArrayList<Directo
 
     override fun getIsItemSelectable(position: Int) = true
 
+    override fun getItemSelectionKey(position: Int) = dirs.getOrNull(position)?.path?.hashCode()
+
+    override fun getItemKeyPosition(key: Int) = dirs.indexOfFirst { it.path.hashCode() == key }
+
     override fun onViewRecycled(holder: ViewHolder) {
         super.onViewRecycled(holder)
-        if (!activity.isActivityDestroyed()) {
-            Glide.with(activity).clear(holder.itemView?.dir_thumbnail!!)
+        if (!activity.isDestroyed) {
+            Glide.with(activity).clear(holder.itemView.dir_thumbnail!!)
         }
     }
 
     private fun checkHideBtnVisibility(menu: Menu) {
         var hiddenCnt = 0
         var unhiddenCnt = 0
-        selectedPositions.mapNotNull { dirs.getOrNull(it)?.path }.forEach {
+        getSelectedPaths().forEach {
             if (File(it).doesThisOrParentHaveNoMedia()) {
                 hiddenCnt++
             } else {
@@ -143,7 +136,7 @@ class DirectoryAdapter(activity: BaseSimpleActivity, var dirs: ArrayList<Directo
         val pinnedFolders = config.pinnedFolders
         var pinnedCnt = 0
         var unpinnedCnt = 0
-        selectedPositions.mapNotNull { dirs.getOrNull(it)?.path }.forEach {
+        getSelectedPaths().forEach {
             if (pinnedFolders.contains(it)) {
                 pinnedCnt++
             } else {
@@ -156,10 +149,10 @@ class DirectoryAdapter(activity: BaseSimpleActivity, var dirs: ArrayList<Directo
     }
 
     private fun showProperties() {
-        if (selectedPositions.size <= 1) {
-            val path = dirs[selectedPositions.first()].path
+        if (selectedKeys.size <= 1) {
+            val path = getFirstSelectedItemPath() ?: return
             if (path != FAVORITES && path != RECYCLE_BIN) {
-                PropertiesDialog(activity, dirs[selectedPositions.first()].path, config.shouldShowHidden)
+                PropertiesDialog(activity, path, config.shouldShowHidden)
             }
         } else {
             PropertiesDialog(activity, getSelectedPaths().filter { it != FAVORITES && it != RECYCLE_BIN }.toMutableList(), config.shouldShowHidden)
@@ -167,7 +160,7 @@ class DirectoryAdapter(activity: BaseSimpleActivity, var dirs: ArrayList<Directo
     }
 
     private fun renameDir() {
-        val firstDir = dirs[selectedPositions.first()]
+        val firstDir = getFirstSelectedItem() ?: return
         val sourcePath = firstDir.path
         val dir = File(sourcePath)
         if (activity.isAStorageRootFolder(dir.absolutePath)) {
@@ -283,18 +276,6 @@ class DirectoryAdapter(activity: BaseSimpleActivity, var dirs: ArrayList<Directo
                         notifyItemRemoved(it)
                     }
 
-                    val newViewHolders = SparseArray<ViewHolder>()
-                    val cnt = viewHolders.size()
-                    for (i in 0..cnt) {
-                        if (affectedPositions.contains(i)) {
-                            continue
-                        }
-
-                        val view = viewHolders.get(i, null)
-                        val newIndex = i - selectedPositions.count { it <= i }
-                        newViewHolders.put(newIndex, view)
-                    }
-                    viewHolders = newViewHolders
                     currentDirectoriesHash = newDirs.hashCode()
                     dirs = newDirs
 
@@ -330,9 +311,9 @@ class DirectoryAdapter(activity: BaseSimpleActivity, var dirs: ArrayList<Directo
 
     private fun pinFolders(pin: Boolean) {
         if (pin) {
-            config.addPinnedFolders(getSelectedPaths())
+            config.addPinnedFolders(getSelectedPaths().toHashSet())
         } else {
-            config.removePinnedFolders(getSelectedPaths())
+            config.removePinnedFolders(getSelectedPaths().toHashSet())
         }
 
         pinnedFolders = config.pinnedFolders
@@ -344,12 +325,11 @@ class DirectoryAdapter(activity: BaseSimpleActivity, var dirs: ArrayList<Directo
     private fun copyMoveTo(isCopyOperation: Boolean) {
         val paths = ArrayList<String>()
         val showHidden = activity.config.shouldShowHidden
-        selectedPositions.forEach {
-            val path = dirs[it].path
-            if (path.startsWith(OTG_PATH)) {
-                paths.addAll(getOTGFilePaths(path, showHidden))
-            } else if (path != FAVORITES) {
-                File(path).listFiles()?.filter {
+        getSelectedPaths().forEach {
+            if (it.startsWith(OTG_PATH)) {
+                paths.addAll(getOTGFilePaths(it, showHidden))
+            } else if (it != FAVORITES) {
+                File(it).listFiles()?.filter {
                     !activity.getIsPathDirectory(it.absolutePath) && it.isMediaFile() && (showHidden || !it.name.startsWith('.'))
                 }?.mapTo(paths) { it.absolutePath }
             }
@@ -378,9 +358,9 @@ class DirectoryAdapter(activity: BaseSimpleActivity, var dirs: ArrayList<Directo
         if (config.skipDeleteConfirmation) {
             deleteFolders()
         } else {
-            val itemsCnt = selectedPositions.size
+            val itemsCnt = selectedKeys.size
             val items = resources.getQuantityString(R.plurals.delete_items, itemsCnt, itemsCnt)
-            val fileDirItem = dirs.getOrNull(selectedPositions.first()) ?: return
+            val fileDirItem = getFirstSelectedItem() ?: return
             val baseString = if (!config.useRecycleBin || (isOneItemSelected() && fileDirItem.isRecycleBin()) || (isOneItemSelected() && fileDirItem.areFavorites())) {
                 R.string.deletion_confirmation
             } else {
@@ -397,59 +377,49 @@ class DirectoryAdapter(activity: BaseSimpleActivity, var dirs: ArrayList<Directo
     }
 
     private fun deleteFolders() {
-        if (selectedPositions.isEmpty()) {
+        if (selectedKeys.isEmpty()) {
             return
         }
 
-        val folders = ArrayList<File>(selectedPositions.size)
-        val removeFolders = ArrayList<Directory>(selectedPositions.size)
-
         var SAFPath = ""
-        selectedPositions.forEach {
-            if (dirs.size > it) {
-                val path = dirs[it].path
-                if (activity.needsStupidWritePermissions(path) && config.treeUri.isEmpty()) {
-                    SAFPath = path
-                }
+        val selectedDirs = getSelectedItems()
+        selectedDirs.forEach {
+            val path = it.path
+            if (activity.needsStupidWritePermissions(path) && config.treeUri.isEmpty()) {
+                SAFPath = path
             }
         }
 
         activity.handleSAFDialog(SAFPath) {
-            selectedPositions.sortedDescending().forEach {
-                val directory = dirs.getOrNull(it)
-                if (directory != null) {
-                    if (directory.areFavorites() || directory.isRecycleBin()) {
-                        if (directory.isRecycleBin()) {
-                            tryEmptyRecycleBin(false)
-                        } else {
-                            Thread {
-                                activity.galleryDB.MediumDao().clearFavorites()
-                                listener?.refreshItems()
-                            }.start()
-                        }
-
-                        if (selectedPositions.size == 1) {
-                            finishActMode()
-                        } else {
-                            selectedPositions.remove(it)
-                            toggleItemSelection(false, it)
-                        }
+            val foldersToDelete = ArrayList<File>(selectedKeys.size)
+            selectedDirs.forEach {
+                if (it.areFavorites() || it.isRecycleBin()) {
+                    if (it.isRecycleBin()) {
+                        tryEmptyRecycleBin(false)
                     } else {
-                        folders.add(File(directory.path))
-                        removeFolders.add(directory)
+                        Thread {
+                            activity.galleryDB.MediumDao().clearFavorites()
+                            listener?.refreshItems()
+                        }.start()
                     }
+
+                    if (selectedKeys.size == 1) {
+                        finishActMode()
+                    }
+                } else {
+                    foldersToDelete.add(File(it.path))
                 }
             }
 
-            listener?.deleteFolders(folders)
+            listener?.deleteFolders(foldersToDelete)
         }
     }
 
     private fun changeAlbumCover(useDefault: Boolean) {
-        if (selectedPositions.size != 1)
+        if (selectedKeys.size != 1)
             return
 
-        val path = dirs[selectedPositions.first()].path
+        val path = getFirstSelectedItemPath() ?: return
 
         if (useDefault) {
             val albumCovers = getAlbumCoversWithout(path)
@@ -480,15 +450,15 @@ class DirectoryAdapter(activity: BaseSimpleActivity, var dirs: ArrayList<Directo
         listener?.refreshItems()
     }
 
-    private fun getSelectedPaths(): HashSet<String> {
-        val paths = HashSet<String>(selectedPositions.size)
-        selectedPositions.forEach {
-            (dirs.getOrNull(it))?.apply {
-                paths.add(path)
-            }
-        }
-        return paths
-    }
+    private fun getSelectedItems() = dirs.filter { selectedKeys.contains(it.path.hashCode()) } as ArrayList<Directory>
+
+    private fun getSelectedPaths() = getSelectedItems().map { it.path } as ArrayList<String>
+
+    private fun getFirstSelectedItem() = getItemWithKey(selectedKeys.first())
+
+    private fun getFirstSelectedItemPath() = getFirstSelectedItem()?.path
+
+    private fun getItemWithKey(key: Int): Directory? = dirs.firstOrNull { it.path.hashCode() == key }
 
     fun updateDirs(newDirs: ArrayList<Directory>) {
         val directories = newDirs.clone() as ArrayList<Directory>
@@ -516,6 +486,7 @@ class DirectoryAdapter(activity: BaseSimpleActivity, var dirs: ArrayList<Directo
     }
 
     private fun setupView(view: View, directory: Directory) {
+        val isSelected = selectedKeys.contains(directory.path.hashCode())
         view.apply {
             dir_name.text = directory.name
             dir_path?.text = "${directory.path.substringBeforeLast("/")}/"
@@ -528,6 +499,11 @@ class DirectoryAdapter(activity: BaseSimpleActivity, var dirs: ArrayList<Directo
                 else -> TYPE_IMAGES
             }
 
+            dir_check?.beVisibleIf(isSelected)
+            if (isSelected) {
+                dir_check.background?.applyColorFilter(primaryColor)
+            }
+
             activity.loadImage(thumbnailType, directory.tmb, dir_thumbnail, scrollHorizontally, animateGifs, cropThumbnails)
             dir_pin.beVisibleIf(pinnedFolders.contains(directory.path))
             dir_location.beVisibleIf(directory.location != LOCAITON_INTERNAL)
diff --git a/app/src/main/kotlin/com/simplemobiletools/gallery/adapters/FiltersAdapter.kt b/app/src/main/kotlin/com/simplemobiletools/gallery/adapters/FiltersAdapter.kt
index 046abda1f..db8aa9c7d 100644
--- a/app/src/main/kotlin/com/simplemobiletools/gallery/adapters/FiltersAdapter.kt
+++ b/app/src/main/kotlin/com/simplemobiletools/gallery/adapters/FiltersAdapter.kt
@@ -1,37 +1,34 @@
 package com.simplemobiletools.gallery.adapters
 
 import android.content.Context
-import android.graphics.drawable.Drawable
 import android.view.LayoutInflater
 import android.view.View
 import android.view.ViewGroup
 import androidx.recyclerview.widget.RecyclerView
 import com.simplemobiletools.gallery.R
-import com.simplemobiletools.gallery.interfaces.FilterAdapterListener
 import com.simplemobiletools.gallery.models.FilterItem
 import kotlinx.android.synthetic.main.editor_filter_item.view.*
 import java.util.*
 
-class FiltersAdapter(val context: Context, val filterItems: ArrayList<FilterItem>, val itemClick: (Int) -> Unit) : RecyclerView.Adapter<FiltersAdapter.ViewHolder>(),
-        FilterAdapterListener {
+class FiltersAdapter(val context: Context, val filterItems: ArrayList<FilterItem>, val itemClick: (Int) -> Unit) : RecyclerView.Adapter<FiltersAdapter.ViewHolder>() {
 
     private var currentSelection = filterItems.first()
     private var strokeBackground = context.resources.getDrawable(R.drawable.stroke_background)
 
     override fun onBindViewHolder(holder: ViewHolder, position: Int) {
-        holder.bindView(filterItems[position], strokeBackground)
+        holder.bindView(filterItems[position])
     }
 
     override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): ViewHolder {
         val view = LayoutInflater.from(parent.context).inflate(R.layout.editor_filter_item, parent, false)
-        return ViewHolder(view, this)
+        return ViewHolder(view)
     }
 
     override fun getItemCount() = filterItems.size
 
-    override fun getCurrentFilter() = currentSelection
+    fun getCurrentFilter() = currentSelection
 
-    override fun setCurrentFilter(position: Int) {
+    private fun setCurrentFilter(position: Int) {
         val filterItem = filterItems.getOrNull(position) ?: return
         if (currentSelection != filterItem) {
             currentSelection = filterItem
@@ -40,19 +37,19 @@ class FiltersAdapter(val context: Context, val filterItems: ArrayList<FilterItem
         }
     }
 
-    class ViewHolder(view: View, val filterAdapterListener: FilterAdapterListener) : RecyclerView.ViewHolder(view) {
-        fun bindView(filterItem: FilterItem, strokeBackground: Drawable): View {
+    inner class ViewHolder(view: View) : RecyclerView.ViewHolder(view) {
+        fun bindView(filterItem: FilterItem): View {
             itemView.apply {
                 editor_filter_item_label.text = filterItem.filter.name
                 editor_filter_item_thumbnail.setImageBitmap(filterItem.bitmap)
-                editor_filter_item_thumbnail.background = if (filterAdapterListener.getCurrentFilter() == filterItem) {
+                editor_filter_item_thumbnail.background = if (getCurrentFilter() == filterItem) {
                     strokeBackground
                 } else {
                     null
                 }
 
                 setOnClickListener {
-                    filterAdapterListener.setCurrentFilter(adapterPosition)
+                    setCurrentFilter(adapterPosition)
                 }
             }
             return itemView
diff --git a/app/src/main/kotlin/com/simplemobiletools/gallery/adapters/ManageFoldersAdapter.kt b/app/src/main/kotlin/com/simplemobiletools/gallery/adapters/ManageFoldersAdapter.kt
index 14a493338..592c00d79 100644
--- a/app/src/main/kotlin/com/simplemobiletools/gallery/adapters/ManageFoldersAdapter.kt
+++ b/app/src/main/kotlin/com/simplemobiletools/gallery/adapters/ManageFoldersAdapter.kt
@@ -25,12 +25,6 @@ class ManageFoldersAdapter(activity: BaseSimpleActivity, var folders: ArrayList<
 
     override fun prepareActionMode(menu: Menu) {}
 
-    override fun prepareItemSelection(viewHolder: ViewHolder) {}
-
-    override fun markViewHolderSelection(select: Boolean, viewHolder: ViewHolder?) {
-        viewHolder?.itemView?.manage_folder_holder?.isSelected = select
-    }
-
     override fun actionItemPressed(id: Int) {
         when (id) {
             R.id.cab_remove -> removeSelection()
@@ -41,20 +35,27 @@ class ManageFoldersAdapter(activity: BaseSimpleActivity, var folders: ArrayList<
 
     override fun getIsItemSelectable(position: Int) = true
 
+    override fun getItemSelectionKey(position: Int) = folders.getOrNull(position)?.hashCode()
+
+    override fun getItemKeyPosition(key: Int) = folders.indexOfFirst { it.hashCode() == key }
+
     override fun onCreateViewHolder(parent: ViewGroup, viewType: Int) = createViewHolder(R.layout.item_manage_folder, parent)
 
     override fun onBindViewHolder(holder: ViewHolder, position: Int) {
         val folder = folders[position]
-        val view = holder.bindView(folder, true, true) { itemView, adapterPosition ->
+        holder.bindView(folder, true, true) { itemView, adapterPosition ->
             setupView(itemView, folder)
         }
-        bindViewHolder(holder, position, view)
+        bindViewHolder(holder)
     }
 
     override fun getItemCount() = folders.size
 
+    private fun getSelectedItems() = folders.filter { selectedKeys.contains(it.hashCode()) } as ArrayList<String>
+
     private fun setupView(view: View, folder: String) {
         view.apply {
+            manage_folder_holder?.isSelected = selectedKeys.contains(folder.hashCode())
             manage_folder_title.apply {
                 text = folder
                 setTextColor(config.textColor)
@@ -63,20 +64,20 @@ class ManageFoldersAdapter(activity: BaseSimpleActivity, var folders: ArrayList<
     }
 
     private fun removeSelection() {
-        val removeFolders = ArrayList<String>(selectedPositions.size)
+        val removeFolders = ArrayList<String>(selectedKeys.size)
+        val positions = getSelectedItemPositions()
 
-        selectedPositions.sortedDescending().forEach {
-            val folder = folders[it]
-            removeFolders.add(folder)
+        getSelectedItems().forEach {
+            removeFolders.add(it)
             if (isShowingExcludedFolders) {
-                config.removeExcludedFolder(folder)
+                config.removeExcludedFolder(it)
             } else {
-                config.removeIncludedFolder(folder)
+                config.removeIncludedFolder(it)
             }
         }
 
         folders.removeAll(removeFolders)
-        removeSelectedItems()
+        removeSelectedItems(positions)
         if (folders.isEmpty()) {
             listener?.refreshItems()
         }
diff --git a/app/src/main/kotlin/com/simplemobiletools/gallery/adapters/ManageHiddenFoldersAdapter.kt b/app/src/main/kotlin/com/simplemobiletools/gallery/adapters/ManageHiddenFoldersAdapter.kt
index 101b12764..95e2c053f 100644
--- a/app/src/main/kotlin/com/simplemobiletools/gallery/adapters/ManageHiddenFoldersAdapter.kt
+++ b/app/src/main/kotlin/com/simplemobiletools/gallery/adapters/ManageHiddenFoldersAdapter.kt
@@ -27,12 +27,6 @@ class ManageHiddenFoldersAdapter(activity: BaseSimpleActivity, var folders: Arra
 
     override fun prepareActionMode(menu: Menu) {}
 
-    override fun prepareItemSelection(viewHolder: ViewHolder) {}
-
-    override fun markViewHolderSelection(select: Boolean, viewHolder: ViewHolder?) {
-        viewHolder?.itemView?.manage_folder_holder?.isSelected = select
-    }
-
     override fun actionItemPressed(id: Int) {
         when (id) {
             R.id.cab_unhide -> tryUnhideFolders()
@@ -43,20 +37,27 @@ class ManageHiddenFoldersAdapter(activity: BaseSimpleActivity, var folders: Arra
 
     override fun getIsItemSelectable(position: Int) = true
 
+    override fun getItemSelectionKey(position: Int) = folders.getOrNull(position)?.hashCode()
+
+    override fun getItemKeyPosition(key: Int) = folders.indexOfFirst { it.hashCode() == key }
+
     override fun onCreateViewHolder(parent: ViewGroup, viewType: Int) = createViewHolder(R.layout.item_manage_folder, parent)
 
     override fun onBindViewHolder(holder: ViewHolder, position: Int) {
         val folder = folders[position]
-        val view = holder.bindView(folder, true, true) { itemView, adapterPosition ->
+        holder.bindView(folder, true, true) { itemView, adapterPosition ->
             setupView(itemView, folder)
         }
-        bindViewHolder(holder, position, view)
+        bindViewHolder(holder)
     }
 
     override fun getItemCount() = folders.size
 
+    private fun getSelectedItems() = folders.filter { selectedKeys.contains(it.hashCode()) } as ArrayList<String>
+
     private fun setupView(view: View, folder: String) {
         view.apply {
+            manage_folder_holder?.isSelected = selectedKeys.contains(folder.hashCode())
             manage_folder_title.apply {
                 text = folder
                 setTextColor(config.textColor)
@@ -65,12 +66,12 @@ class ManageHiddenFoldersAdapter(activity: BaseSimpleActivity, var folders: Arra
     }
 
     private fun tryUnhideFolders() {
-        val removeFolders = ArrayList<String>(selectedPositions.size)
+        val removeFolders = ArrayList<String>(selectedKeys.size)
 
         val sdCardPaths = ArrayList<String>()
-        selectedPositions.forEach {
-            if (activity.isPathOnSD(folders[it])) {
-                sdCardPaths.add(folders[it])
+        getSelectedItems().forEach {
+            if (activity.isPathOnSD(it)) {
+                sdCardPaths.add(it)
             }
         }
 
@@ -84,14 +85,14 @@ class ManageHiddenFoldersAdapter(activity: BaseSimpleActivity, var folders: Arra
     }
 
     private fun unhideFolders(removeFolders: ArrayList<String>) {
-        selectedPositions.sortedDescending().forEach {
-            val folder = folders[it]
-            removeFolders.add(folder)
-            activity.removeNoMedia(folder)
+        val position = getSelectedItemPositions()
+        getSelectedItems().forEach {
+            removeFolders.add(it)
+            activity.removeNoMedia(it)
         }
 
         folders.removeAll(removeFolders)
-        removeSelectedItems()
+        removeSelectedItems(position)
         if (folders.isEmpty()) {
             listener?.refreshItems()
         }
diff --git a/app/src/main/kotlin/com/simplemobiletools/gallery/adapters/MediaAdapter.kt b/app/src/main/kotlin/com/simplemobiletools/gallery/adapters/MediaAdapter.kt
index d88895b59..06ef2b350 100644
--- a/app/src/main/kotlin/com/simplemobiletools/gallery/adapters/MediaAdapter.kt
+++ b/app/src/main/kotlin/com/simplemobiletools/gallery/adapters/MediaAdapter.kt
@@ -61,14 +61,6 @@ class MediaAdapter(activity: BaseSimpleActivity, var media: MutableList<Thumbnai
 
     override fun getActionMenuId() = R.menu.cab_media
 
-    override fun prepareItemSelection(viewHolder: ViewHolder) {
-        viewHolder.itemView?.medium_check?.background?.applyColorFilter(primaryColor)
-    }
-
-    override fun markViewHolderSelection(select: Boolean, viewHolder: ViewHolder?) {
-        viewHolder?.itemView?.medium_check?.beVisibleIf(select)
-    }
-
     override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): ViewHolder {
         val layoutType = if (viewType == ITEM_SECTION) {
             R.layout.thumbnail_section
@@ -89,14 +81,14 @@ class MediaAdapter(activity: BaseSimpleActivity, var media: MutableList<Thumbnai
         }
 
         val allowLongPress = !allowMultiplePicks && tmbItem is Medium
-        val view = holder.bindView(tmbItem, tmbItem is Medium, allowLongPress) { itemView, adapterPosition ->
+        holder.bindView(tmbItem, tmbItem is Medium, allowLongPress) { itemView, adapterPosition ->
             if (tmbItem is Medium) {
                 setupThumbnail(itemView, tmbItem)
             } else {
                 setupSection(itemView, tmbItem as ThumbnailSection)
             }
         }
-        bindViewHolder(holder, position, view)
+        bindViewHolder(holder)
     }
 
     override fun getItemCount() = media.size
@@ -112,9 +104,9 @@ class MediaAdapter(activity: BaseSimpleActivity, var media: MutableList<Thumbnai
 
     override fun prepareActionMode(menu: Menu) {
         menu.apply {
-            findItem(R.id.cab_rename).isVisible = isOneItemSelected() && getSelectedMedia().firstOrNull()?.getIsInRecycleBin() == false
+            findItem(R.id.cab_rename).isVisible = isOneItemSelected() && getSelectedItems().firstOrNull()?.getIsInRecycleBin() == false
             findItem(R.id.cab_open_with).isVisible = isOneItemSelected()
-            findItem(R.id.cab_confirm_selection).isVisible = isAGetIntent && allowMultiplePicks && selectedPositions.size > 0
+            findItem(R.id.cab_confirm_selection).isVisible = isAGetIntent && allowMultiplePicks && selectedKeys.size > 0
             findItem(R.id.cab_restore_recycle_bin_files).isVisible = getSelectedPaths().all { it.startsWith(activity.filesDir.absolutePath) }
 
             checkHideBtnVisibility(this)
@@ -123,7 +115,7 @@ class MediaAdapter(activity: BaseSimpleActivity, var media: MutableList<Thumbnai
     }
 
     override fun actionItemPressed(id: Int) {
-        if (selectedPositions.isEmpty()) {
+        if (selectedKeys.isEmpty()) {
             return
         }
 
@@ -141,9 +133,9 @@ class MediaAdapter(activity: BaseSimpleActivity, var media: MutableList<Thumbnai
             R.id.cab_copy_to -> copyMoveTo(true)
             R.id.cab_move_to -> copyMoveTo(false)
             R.id.cab_select_all -> selectAll()
-            R.id.cab_open_with -> activity.openPath(getCurrentPath(), true)
+            R.id.cab_open_with -> openPath()
             R.id.cab_fix_date_taken -> fixDateTaken()
-            R.id.cab_set_as -> activity.setAs(getCurrentPath())
+            R.id.cab_set_as -> setAs()
             R.id.cab_delete -> checkDeleteConfirmation()
         }
     }
@@ -152,9 +144,13 @@ class MediaAdapter(activity: BaseSimpleActivity, var media: MutableList<Thumbnai
 
     override fun getIsItemSelectable(position: Int) = !isASectionTitle(position)
 
+    override fun getItemSelectionKey(position: Int) = (media.getOrNull(position) as? Medium)?.path?.hashCode()
+
+    override fun getItemKeyPosition(key: Int) = media.indexOfFirst { (it as? Medium)?.path?.hashCode() == key }
+
     override fun onViewRecycled(holder: ViewHolder) {
         super.onViewRecycled(holder)
-        if (!activity.isActivityDestroyed()) {
+        if (!activity.isDestroyed) {
             val itemView = holder.itemView
             visibleItemPaths.remove(itemView?.photo_name?.tag)
             val tmb = itemView?.medium_thumbnail
@@ -169,7 +165,7 @@ class MediaAdapter(activity: BaseSimpleActivity, var media: MutableList<Thumbnai
     private fun checkHideBtnVisibility(menu: Menu) {
         var hiddenCnt = 0
         var unhiddenCnt = 0
-        getSelectedMedia().forEach {
+        getSelectedItems().forEach {
             if (it.isHidden()) {
                 hiddenCnt++
             } else {
@@ -177,7 +173,7 @@ class MediaAdapter(activity: BaseSimpleActivity, var media: MutableList<Thumbnai
             }
         }
 
-        val isInRecycleBin = getSelectedMedia().firstOrNull()?.getIsInRecycleBin() == true
+        val isInRecycleBin = getSelectedItems().firstOrNull()?.getIsInRecycleBin() == true
         menu.findItem(R.id.cab_hide).isVisible = unhiddenCnt > 0 && !isInRecycleBin
         menu.findItem(R.id.cab_unhide).isVisible = hiddenCnt > 0 && !isInRecycleBin
     }
@@ -185,7 +181,7 @@ class MediaAdapter(activity: BaseSimpleActivity, var media: MutableList<Thumbnai
     private fun checkFavoriteBtnVisibility(menu: Menu) {
         var favoriteCnt = 0
         var nonFavoriteCnt = 0
-        getSelectedMedia().forEach {
+        getSelectedItems().forEach {
             if (it.isFavorite) {
                 favoriteCnt++
             } else {
@@ -202,8 +198,9 @@ class MediaAdapter(activity: BaseSimpleActivity, var media: MutableList<Thumbnai
     }
 
     private fun showProperties() {
-        if (selectedPositions.size <= 1) {
-            PropertiesDialog(activity, (media[selectedPositions.first()] as Medium).path, config.shouldShowHidden)
+        if (selectedKeys.size <= 1) {
+            val path = getFirstSelectedItemPath() ?: return
+            PropertiesDialog(activity, path, config.shouldShowHidden)
         } else {
             val paths = getSelectedPaths()
             PropertiesDialog(activity, paths, config.shouldShowHidden)
@@ -211,7 +208,7 @@ class MediaAdapter(activity: BaseSimpleActivity, var media: MutableList<Thumbnai
     }
 
     private fun renameFile() {
-        val oldPath = getCurrentPath()
+        val oldPath = getFirstSelectedItemPath() ?: return
         RenameItemDialog(activity, oldPath) {
             Thread {
                 activity.updateDBMediaPath(oldPath, it)
@@ -226,12 +223,23 @@ class MediaAdapter(activity: BaseSimpleActivity, var media: MutableList<Thumbnai
     }
 
     private fun editFile() {
-        activity.openEditor(getCurrentPath())
+        val path = getFirstSelectedItemPath() ?: return
+        activity.openEditor(path)
+    }
+
+    private fun openPath() {
+        val path = getFirstSelectedItemPath() ?: return
+        activity.openPath(path, true)
+    }
+
+    private fun setAs() {
+        val path = getFirstSelectedItemPath() ?: return
+        activity.setAs(path)
     }
 
     private fun toggleFileVisibility(hide: Boolean) {
         Thread {
-            getSelectedMedia().forEach {
+            getSelectedItems().forEach {
                 activity.toggleFileVisibility(it.path, hide)
             }
             activity.runOnUiThread {
@@ -244,7 +252,7 @@ class MediaAdapter(activity: BaseSimpleActivity, var media: MutableList<Thumbnai
     private fun toggleFavorites(add: Boolean) {
         Thread {
             val mediumDao = activity.galleryDB.MediumDao()
-            getSelectedMedia().forEach {
+            getSelectedItems().forEach {
                 it.isFavorite = add
                 mediumDao.updateFavorite(it.path, add)
             }
@@ -263,9 +271,9 @@ class MediaAdapter(activity: BaseSimpleActivity, var media: MutableList<Thumbnai
     }
 
     private fun shareMedia() {
-        if (selectedPositions.size == 1 && selectedPositions.first() != -1) {
-            activity.shareMediumPath(getSelectedMedia().first().path)
-        } else if (selectedPositions.size > 1) {
+        if (selectedKeys.size == 1 && selectedKeys.first() != -1) {
+            activity.shareMediumPath(getSelectedItems().first().path)
+        } else if (selectedKeys.size > 1) {
             activity.shareMediaPaths(getSelectedPaths())
         }
     }
@@ -345,7 +353,7 @@ class MediaAdapter(activity: BaseSimpleActivity, var media: MutableList<Thumbnai
     }
 
     private fun askConfirmDelete() {
-        val items = resources.getQuantityString(R.plurals.delete_items, selectedPositions.size, selectedPositions.size)
+        val items = resources.getQuantityString(R.plurals.delete_items, selectedKeys.size, selectedKeys.size)
         val isRecycleBin = getSelectedPaths().first().startsWith(activity.filesDir.absolutePath)
         val baseString = if (config.useRecycleBin && !isRecycleBin) R.string.move_to_recycle_bin_confirmation else R.string.deletion_confirmation
         val question = String.format(resources.getString(baseString), items)
@@ -355,48 +363,35 @@ class MediaAdapter(activity: BaseSimpleActivity, var media: MutableList<Thumbnai
         }
     }
 
-    private fun getCurrentPath() = (media[selectedPositions.first()] as Medium).path
-
     private fun deleteFiles() {
-        if (selectedPositions.isEmpty()) {
+        if (selectedKeys.isEmpty()) {
             return
         }
 
-        val fileDirItems = ArrayList<FileDirItem>(selectedPositions.size)
-        val removeMedia = ArrayList<Medium>(selectedPositions.size)
-
-        if (media.size <= selectedPositions.first()) {
-            finishActMode()
-            return
-        }
-
-        val SAFPath = (media[selectedPositions.first()] as Medium).path
+        val SAFPath = getFirstSelectedItemPath() ?: return
         activity.handleSAFDialog(SAFPath) {
-            selectedPositions.sortedDescending().forEach {
-                val thumbnailItem = media.getOrNull(it)
-                if (thumbnailItem is Medium) {
-                    fileDirItems.add(FileDirItem(thumbnailItem.path, thumbnailItem.name))
-                    removeMedia.add(thumbnailItem)
-                }
+            val fileDirItems = ArrayList<FileDirItem>(selectedKeys.size)
+            val removeMedia = ArrayList<Medium>(selectedKeys.size)
+            val position = getSelectedItemPositions()
+
+            getSelectedItems().forEach {
+                fileDirItems.add(FileDirItem(it.path, it.name))
+                removeMedia.add(it)
             }
 
             media.removeAll(removeMedia)
             listener?.tryDeleteFiles(fileDirItems)
-            removeSelectedItems()
+            removeSelectedItems(position)
         }
     }
 
-    private fun getSelectedMedia(): List<Medium> {
-        val selectedMedia = ArrayList<Medium>(selectedPositions.size)
-        selectedPositions.forEach {
-            (media.getOrNull(it) as? Medium)?.apply {
-                selectedMedia.add(this)
-            }
-        }
-        return selectedMedia
-    }
+    private fun getSelectedItems() = media.filter { selectedKeys.contains((it as? Medium)?.path?.hashCode()) } as ArrayList<Medium>
 
-    private fun getSelectedPaths() = getSelectedMedia().map { it.path } as ArrayList<String>
+    private fun getSelectedPaths() = getSelectedItems().map { it.path } as ArrayList<String>
+
+    private fun getFirstSelectedItemPath() = getItemWithKey(selectedKeys.first())?.path
+
+    private fun getItemWithKey(key: Int): Medium? = media.firstOrNull { (it as? Medium)?.path?.hashCode() == key } as? Medium
 
     fun updateMedia(newMedia: ArrayList<ThumbnailItem>) {
         val thumbnailItems = newMedia.clone() as ArrayList<ThumbnailItem>
@@ -437,12 +432,18 @@ class MediaAdapter(activity: BaseSimpleActivity, var media: MutableList<Thumbnai
     fun getItemBubbleText(position: Int, sorting: Int) = (media[position] as? Medium)?.getBubbleText(sorting)
 
     private fun setupThumbnail(view: View, medium: Medium) {
+        val isSelected = selectedKeys.contains(medium.path.hashCode())
         view.apply {
             play_outline.beVisibleIf(medium.isVideo())
             photo_name.beVisibleIf(displayFilenames || isListViewType)
             photo_name.text = medium.name
             photo_name.tag = medium.path
 
+            medium_check?.beVisibleIf(isSelected)
+            if (isSelected) {
+                medium_check?.background?.applyColorFilter(primaryColor)
+            }
+
             var path = medium.path
             if (hasOTGConnected && path.startsWith(OTG_PATH)) {
                 path = path.getOTGPublicPath(context)
diff --git a/app/src/main/kotlin/com/simplemobiletools/gallery/adapters/MyPagerAdapter.kt b/app/src/main/kotlin/com/simplemobiletools/gallery/adapters/MyPagerAdapter.kt
index 7d0b6fe5c..10190b4a1 100644
--- a/app/src/main/kotlin/com/simplemobiletools/gallery/adapters/MyPagerAdapter.kt
+++ b/app/src/main/kotlin/com/simplemobiletools/gallery/adapters/MyPagerAdapter.kt
@@ -2,11 +2,11 @@ package com.simplemobiletools.gallery.adapters
 
 import android.os.Bundle
 import android.os.Parcelable
+import android.view.ViewGroup
 import androidx.fragment.app.Fragment
 import androidx.fragment.app.FragmentManager
 import androidx.fragment.app.FragmentStatePagerAdapter
 import androidx.viewpager.widget.PagerAdapter
-import android.view.ViewGroup
 import com.simplemobiletools.gallery.activities.ViewPagerActivity
 import com.simplemobiletools.gallery.fragments.PhotoFragment
 import com.simplemobiletools.gallery.fragments.VideoFragment
diff --git a/app/src/main/kotlin/com/simplemobiletools/gallery/extensions/Activity.kt b/app/src/main/kotlin/com/simplemobiletools/gallery/extensions/Activity.kt
index 8993ebce3..d70cd507f 100644
--- a/app/src/main/kotlin/com/simplemobiletools/gallery/extensions/Activity.kt
+++ b/app/src/main/kotlin/com/simplemobiletools/gallery/extensions/Activity.kt
@@ -3,8 +3,8 @@ package com.simplemobiletools.gallery.extensions
 import android.app.Activity
 import android.content.Intent
 import android.provider.MediaStore
-import androidx.appcompat.app.AppCompatActivity
 import android.view.View
+import androidx.appcompat.app.AppCompatActivity
 import com.simplemobiletools.commons.activities.BaseSimpleActivity
 import com.simplemobiletools.commons.dialogs.ConfirmationDialog
 import com.simplemobiletools.commons.extensions.*
@@ -60,8 +60,8 @@ fun Activity.launchCamera() {
 }
 
 fun SimpleActivity.launchAbout() {
-    val licenses = LICENSE_GLIDE or LICENSE_CROPPER or LICENSE_MULTISELECT or LICENSE_RTL or LICENSE_SUBSAMPLING or LICENSE_PATTERN or
-            LICENSE_REPRINT or LICENSE_GIF_DRAWABLE or LICENSE_PHOTOVIEW or LICENSE_PICASSO or LICENSE_EXOPLAYER or LICENSE_PANORAMA_VIEW or LICENSE_SANSELAN or LICENSE_FILTERS
+    val licenses = LICENSE_GLIDE or LICENSE_CROPPER or LICENSE_RTL or LICENSE_SUBSAMPLING or LICENSE_PATTERN or LICENSE_REPRINT or LICENSE_GIF_DRAWABLE or
+            LICENSE_PHOTOVIEW or LICENSE_PICASSO or LICENSE_EXOPLAYER or LICENSE_PANORAMA_VIEW or LICENSE_SANSELAN or LICENSE_FILTERS
 
     val faqItems = arrayListOf(
             FAQItem(R.string.faq_5_title_commons, R.string.faq_5_text_commons),
diff --git a/app/src/main/kotlin/com/simplemobiletools/gallery/extensions/Context.kt b/app/src/main/kotlin/com/simplemobiletools/gallery/extensions/Context.kt
index 41cf947d1..45808d5a0 100644
--- a/app/src/main/kotlin/com/simplemobiletools/gallery/extensions/Context.kt
+++ b/app/src/main/kotlin/com/simplemobiletools/gallery/extensions/Context.kt
@@ -8,7 +8,6 @@ import android.database.sqlite.SQLiteException
 import android.graphics.Point
 import android.graphics.drawable.PictureDrawable
 import android.media.AudioManager
-import android.os.Build
 import android.provider.MediaStore
 import android.view.WindowManager
 import android.widget.ImageView
@@ -88,8 +87,7 @@ val Context.usableScreenSize: Point
 val Context.realScreenSize: Point
     get() {
         val size = Point()
-        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.JELLY_BEAN_MR1)
-            windowManager.defaultDisplay.getRealSize(size)
+        windowManager.defaultDisplay.getRealSize(size)
         return size
     }
 
diff --git a/app/src/main/kotlin/com/simplemobiletools/gallery/fragments/PhotoFragment.kt b/app/src/main/kotlin/com/simplemobiletools/gallery/fragments/PhotoFragment.kt
index 1da94e93e..f0581f9ce 100644
--- a/app/src/main/kotlin/com/simplemobiletools/gallery/fragments/PhotoFragment.kt
+++ b/app/src/main/kotlin/com/simplemobiletools/gallery/fragments/PhotoFragment.kt
@@ -1,6 +1,5 @@
 package com.simplemobiletools.gallery.fragments
 
-import android.annotation.SuppressLint
 import android.content.Intent
 import android.content.res.Configuration
 import android.graphics.Bitmap
@@ -29,8 +28,6 @@ import com.davemorrissey.labs.subscaleview.ImageSource
 import com.davemorrissey.labs.subscaleview.SubsamplingScaleImageView
 import com.simplemobiletools.commons.extensions.*
 import com.simplemobiletools.commons.helpers.OTG_PATH
-import com.simplemobiletools.commons.helpers.isJellyBean1Plus
-import com.simplemobiletools.commons.helpers.isLollipopPlus
 import com.simplemobiletools.gallery.R
 import com.simplemobiletools.gallery.activities.PanoramaActivity
 import com.simplemobiletools.gallery.activities.PhotoActivity
@@ -208,18 +205,11 @@ class PhotoFragment : ViewPagerFragment() {
         }
     }
 
-    @SuppressLint("NewApi")
     private fun measureScreen() {
         val metrics = DisplayMetrics()
-        if (isJellyBean1Plus()) {
-            activity!!.windowManager.defaultDisplay.getRealMetrics(metrics)
-            ViewPagerActivity.screenWidth = metrics.widthPixels
-            ViewPagerActivity.screenHeight = metrics.heightPixels
-        } else {
-            activity!!.windowManager.defaultDisplay.getMetrics(metrics)
-            ViewPagerActivity.screenWidth = metrics.widthPixels
-            ViewPagerActivity.screenHeight = metrics.heightPixels
-        }
+        activity!!.windowManager.defaultDisplay.getRealMetrics(metrics)
+        ViewPagerActivity.screenWidth = metrics.widthPixels
+        ViewPagerActivity.screenHeight = metrics.heightPixels
     }
 
     private fun photoFragmentVisibilityChanged(isVisible: Boolean) {
@@ -280,7 +270,7 @@ class PhotoFragment : ViewPagerFragment() {
     }
 
     private fun loadSVG() {
-        Glide.with(this)
+        Glide.with(context!!)
                 .`as`(PictureDrawable::class.java)
                 .listener(SvgSoftwareLayerSetter())
                 .load(medium.path)
@@ -440,7 +430,7 @@ class PhotoFragment : ViewPagerFragment() {
             false
         }
 
-        view.panorama_outline.beVisibleIf(isPanorama && isLollipopPlus())
+        view.panorama_outline.beVisibleIf(isPanorama)
     }
 
     private fun getImageOrientation(): Int {
@@ -514,7 +504,7 @@ class PhotoFragment : ViewPagerFragment() {
 
     override fun onDestroyView() {
         super.onDestroyView()
-        if (activity?.isActivityDestroyed() == false) {
+        if (activity?.isDestroyed == false) {
             view.subsampling_view.recycle()
         }
         loadZoomableViewHandler.removeCallbacksAndMessages(null)
diff --git a/app/src/main/kotlin/com/simplemobiletools/gallery/fragments/VideoFragment.kt b/app/src/main/kotlin/com/simplemobiletools/gallery/fragments/VideoFragment.kt
index 470a061e0..751b98e4e 100644
--- a/app/src/main/kotlin/com/simplemobiletools/gallery/fragments/VideoFragment.kt
+++ b/app/src/main/kotlin/com/simplemobiletools/gallery/fragments/VideoFragment.kt
@@ -1,13 +1,11 @@
 package com.simplemobiletools.gallery.fragments
 
-import android.annotation.TargetApi
 import android.content.res.Configuration
 import android.graphics.Point
 import android.graphics.SurfaceTexture
 import android.media.AudioManager
 import android.media.MediaMetadataRetriever
 import android.net.Uri
-import android.os.Build
 import android.os.Bundle
 import android.os.Handler
 import android.util.DisplayMetrics
@@ -28,7 +26,6 @@ import com.google.android.exoplayer2.upstream.DataSpec
 import com.google.android.exoplayer2.upstream.FileDataSource
 import com.google.android.exoplayer2.video.VideoListener
 import com.simplemobiletools.commons.extensions.*
-import com.simplemobiletools.commons.helpers.isJellyBean1Plus
 import com.simplemobiletools.gallery.R
 import com.simplemobiletools.gallery.activities.VideoActivity
 import com.simplemobiletools.gallery.extensions.*
@@ -312,27 +309,21 @@ class VideoFragment : ViewPagerFragment(), TextureView.SurfaceTextureListener, S
     }
 
     private fun hasNavBar(): Boolean {
-        return if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.JELLY_BEAN_MR1) {
-            val display = context!!.windowManager.defaultDisplay
+        val display = context!!.windowManager.defaultDisplay
 
-            val realDisplayMetrics = DisplayMetrics()
-            display.getRealMetrics(realDisplayMetrics)
+        val realDisplayMetrics = DisplayMetrics()
+        display.getRealMetrics(realDisplayMetrics)
 
-            val realHeight = realDisplayMetrics.heightPixels
-            val realWidth = realDisplayMetrics.widthPixels
+        val realHeight = realDisplayMetrics.heightPixels
+        val realWidth = realDisplayMetrics.widthPixels
 
-            val displayMetrics = DisplayMetrics()
-            display.getMetrics(displayMetrics)
+        val displayMetrics = DisplayMetrics()
+        display.getMetrics(displayMetrics)
 
-            val displayHeight = displayMetrics.heightPixels
-            val displayWidth = displayMetrics.widthPixels
+        val displayHeight = displayMetrics.heightPixels
+        val displayWidth = displayMetrics.widthPixels
 
-            realWidth - displayWidth > 0 || realHeight - displayHeight > 0
-        } else {
-            val hasMenuKey = ViewConfiguration.get(context).hasPermanentMenuKey()
-            val hasBackKey = KeyCharacterMap.deviceHasKey(KeyEvent.KEYCODE_BACK)
-            !hasMenuKey && !hasBackKey
-        }
+        return realWidth - displayWidth > 0 || realHeight - displayHeight > 0
     }
 
     private fun setupTimeHolder() {
@@ -514,7 +505,6 @@ class VideoFragment : ViewPagerFragment(), TextureView.SurfaceTextureListener, S
         }.start()
     }
 
-    @TargetApi(Build.VERSION_CODES.JELLY_BEAN_MR1)
     private fun setVideoSize() {
         if (activity == null || mTextureView == null)
             return
@@ -524,15 +514,10 @@ class VideoFragment : ViewPagerFragment(), TextureView.SurfaceTextureListener, S
         val screenWidth: Int
         val screenHeight: Int
 
-        if (isJellyBean1Plus()) {
-            val realMetrics = DisplayMetrics()
-            display.getRealMetrics(realMetrics)
-            screenWidth = realMetrics.widthPixels
-            screenHeight = realMetrics.heightPixels
-        } else {
-            screenWidth = display.width
-            screenHeight = display.height
-        }
+        val realMetrics = DisplayMetrics()
+        display.getRealMetrics(realMetrics)
+        screenWidth = realMetrics.widthPixels
+        screenHeight = realMetrics.heightPixels
 
         val screenProportion = screenWidth.toFloat() / screenHeight.toFloat()
 
diff --git a/app/src/main/kotlin/com/simplemobiletools/gallery/interfaces/FilterAdapterListener.kt b/app/src/main/kotlin/com/simplemobiletools/gallery/interfaces/FilterAdapterListener.kt
deleted file mode 100644
index 379e9e964..000000000
--- a/app/src/main/kotlin/com/simplemobiletools/gallery/interfaces/FilterAdapterListener.kt
+++ /dev/null
@@ -1,9 +0,0 @@
-package com.simplemobiletools.gallery.interfaces
-
-import com.simplemobiletools.gallery.models.FilterItem
-
-interface FilterAdapterListener {
-    fun getCurrentFilter(): FilterItem
-
-    fun setCurrentFilter(position: Int)
-}
diff --git a/app/src/main/res/values-v21/styles.xml b/app/src/main/res/values-v21/styles.xml
deleted file mode 100644
index 7f1ac50b0..000000000
--- a/app/src/main/res/values-v21/styles.xml
+++ /dev/null
@@ -1,7 +0,0 @@
-<resources>
-
-    <style name="FullScreenTheme" parent="AppTheme.Base">
-        <item name="android:windowTranslucentNavigation">true</item>
-    </style>
-
-</resources>
diff --git a/app/src/main/res/values/styles.xml b/app/src/main/res/values/styles.xml
index 9bb53721a..fdde24e05 100644
--- a/app/src/main/res/values/styles.xml
+++ b/app/src/main/res/values/styles.xml
@@ -4,6 +4,7 @@
 
     <style name="FullScreenTheme.Base" parent="AppTheme">
         <item name="android:windowContentOverlay">@null</item>
+        <item name="android:windowTranslucentNavigation">true</item>
     </style>
 
     <style name="FullScreenTheme" parent="FullScreenTheme.Base"/>
diff --git a/build.gradle b/build.gradle
index 5aab4c3d6..0b0dbc07b 100644
--- a/build.gradle
+++ b/build.gradle
@@ -9,7 +9,7 @@ buildscript {
     }
 
     dependencies {
-        classpath 'com.android.tools.build:gradle:3.2.0'
+        classpath 'com.android.tools.build:gradle:3.2.1'
         classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlin_version"
 
         // NOTE: Do not place your application dependencies here; they belong