To test if the panel is under the cursor we used:
if (geometry().contains(QCursor::pos(screenToFollow()))) {
Unsurprisingly in wayland we don't know the cursor position once it's
left our window. Behaviour seems to be undefined.
We were already using enter and leave events to start the autohide
timer, so we may as well rely on that for tracking state too.
BUG: 377838