KMessageWidget uses KStandardAction::close() to create its "close" action. This automatically sets Ctrl+W as the shortcut for that action. Unfortunately, this shortcut may conflict with application-specific shortcuts. E.g., Dolphin uses Ctrl+W for closing tabs, which means that the user will get an annoying "shortcut conflict" error message if Ctrl+W is pressed while multiple tabs are open, and the current tab has a message shown in a KMessageWidget.

I propose to solve this problem by not using a default shortcut for KMessageWidget's "close" action. I'd prefer to change this in master only to prevent causing trouble for people who might rely on the current behavior.

I don't get a dialog showing the "Ambiguous shortcut" message any more in the described use case.