Compositors may switch from mouse to touch mode when a touch event is received, causing a pointer leave event and subsequent loss of mouse focus.
Don't relinquish mouse focus on surfaces with active touch events. If there are active touch events when pointer focus is lost, the keyboard focus is used as a fallback for relinquishing mouse focus: if, in this case, the keyboard focus is then lost and there are no active touches, mouse focus is lost, and if all touches are raised and there is no keyboard or pointer focus, then the window loses mouse focus.
(cherry picked from commit 21879faf48)