This reverts parts of e4efcea2 and
8e12b2e6.

They are effectively deemed to have happened after the SetCursorPos().

We don't want to clip in the desktop process, but we still need it to call
ungrab_clipping_window() if the process that was previously clipping didn't.
This can happen for example when fullscreen clipping is enabled, but the
corresponding window isn't explicitly destroyed before process exit.

The Mac driver doesn't normally steal focus, but a click on the systray icon
counts as the user giving permission.