KNotes does not open from the plasma control panel. This behaviour only occurs if composite is acitvated and if no other window is open on the desktop. STEPS TO REPRODUCE 1. Activate composite 2. Close all open widows, if there are some open. 3. Click at the KNotes icon on the control panel 4. Nothing happens, KNotes window does not pop up. Now deactivate composite and KNotes will work. Now activate composite again (SHIFT + ALT + F12) and start any program: Knotes will work. Now close the just started program or switch to another virtual desktop, where no window is open: KNotes will not work again. SOFTWARE/OS VERSIONS Linux/KDE Plasma: open Suse Leap 15.2 KDE Plasma Version: 5.18.6 KDE Frameworks Version: 5.71.0 Qt Version: 5.12.7 ADDITIONAL INFORMATION