Fix tooltip triggering

Fix tooltip triggering

Ever since 5b5d2665d373c35f, tooltips don't work properly,
since we get more motion events now, and those keep the
tooltips from appearing. This can be seen e.g. on the icon
in the password entry in widget-factory, or on the section
switcher buttons in the Emoji chooser.

Ignore synthetic motion events for the purposes of
determining whether the user moved the mouse.