SUMMARY If multiple background mode windows are open, closing one of them results in all others not responding to the show/hide shortcut. Opening another background mode window makes the broken windows work again (they toggle visibility when shortcut is pressed). STEPS TO REPRODUCE 1. Open multiple windows in background mode Use show/hide shortcut to confirm it works. 2. Close one of the background mode windows. 3. Try the shortcut again. It will no longer work. 4. Open another background mode window. 5. Try the shortcut again. It will work even for the window that did not work before.
might be intended behaviour: a closed window is a goner. you cannot bring it back up, since it closed and terminated.
I wasn't trying to bring back the closed window, I was trying to toggle the *other* background-mode window.
Can confirm if multiple windows are opened in --background-mode that closing one will stop the shortcut working. Konsole 21.03.70