Regression was introduced in 3372dfcd3e.
Only when platform-specific code can give us the global time of the
last user input event we rely on idle time for notifications hiding.
Fixes#5791.
Use Qt::Dialog instead of Qt::Tool which works better with window
activation / deactivation handling.
Stop displaying the panel on all spaces when the call is established.
Also implement panels that appear in all spaces on macOS.
Using them for calls panels and custom notifications, so it
will be possible to use custom notifications in macOS as well.
John Preston
Gregory K