Make keyboard focus a pointer constraints necessity
This patch changes KWin's pointer constraining behavior by only allowing
constraints if the surface has keyboard focus. In case the client activation
state changes, it rechecks it.
Manually with the pointer constraints test application and opening the
launcher by pressing meta. Also amended autotest.
Reviewers: KWin, graesslin
Reviewed By: KWin, graesslin
Subscribers: graesslin, davidedmundson, kwin
Maniphest Tasks: T8923
Differential Revision: https://phabricator.kde.org/D13492