At least a restart of plasmashell is required for the clipboard
history to be cleared.
+*** XFCE: Selected frame loses focus
+
+This can happen, e.g., in Ediff: when you move between the differences
+by typing into the control frame, input focus unexpectedly switches to
+the buffers where Emacs shows the differences, instead of being left
+in the Ediff control frame.
+
+The reason is a bug in the window manager: it shifts input focus when
+raising a frame. A workaround is to activate the "focus stealing
+prevention" option of the window manager (in XFCE settings, under
+"window manager tweaks", in the "focus" tab).
+
*** CDE: Frames may cover dialogs they created when using CDE.
This can happen if you have "Allow Primary Windows On Top" enabled which