diff --git a/exwm-systemtray.el b/exwm-systemtray.el
index 4f02a78..9ad29ac 100644
--- a/exwm-systemtray.el
+++ b/exwm-systemtray.el
@@ -491,7 +491,9 @@ Argument DATA contains the raw event data."
 (cl-defun exwm-systemtray--init ()
   "Initialize system tray module."
   (exwm--log)
-  (cl-assert (not exwm-systemtray--connection))
+  ;; idempotent initialization
+  (when exwm-systemtray--connection
+    (cl-return-from exwm-systemtray--init))
   (cl-assert (not exwm-systemtray--list))
   (cl-assert (not exwm-systemtray--selection-owner-window))
   (cl-assert (not exwm-systemtray--embedder-window))
diff --git a/exwm-xsettings.el b/exwm-xsettings.el
index 242819f..985c273 100644
--- a/exwm-xsettings.el
+++ b/exwm-xsettings.el
@@ -238,7 +238,9 @@ SERIAL is a sequence number."
   "Initialize the XSETTINGS module."
   (exwm--log)
 
-  (cl-assert (not exwm-xsettings--connection))
+  ;; idempotent initialization
+  (when exwm-xsettings--connection
+    (cl-return-from exwm-xsettings--init))
 
   ;; Connect
   (setq exwm-xsettings--connection (xcb:connect))