Based on a patch from Paul Davis, inject synthetic enter events directly
into the Quartz event stream, instead of trying to synthesize them in GDK.
This seems to magically fix most combo box popup weirdness, I guess
some code is relying on a specfic order of events, or any other state
imposed by the "proper" code path of events coming in the usual way.
The patch also removes _gdk_quartz_events_send_enter_notify_event()
which is now obsolete.
(sortof cherry-pixked from 979e5061a0
but needed manual editing because GdkQuartzWindow.c was renamed
and apparently earlier patches not picked correctly/completely)
In the Quartz backend, there are two methods by which windows are
resized. The first method is fully handled by Quartz and does not appear
in the event stream the application resizes. The second method is when
we resize windows by ourselves. In OS X this happens when a GTK+ resize
grip is used. This resize grip is larger than the Quartz resize grip.
When the resize is started outside the "Quartz area", we have to handle
it by ourselves.
This patch fixes this manual window resizing by ignoring events while we
are in the process of resizing (such that the events actually arrive at
the sendEvent handler of GdkQuartzWindow where this resize is handled).
When the resize has finished we break all grabs such that GDK is not
stuck thinking the cursor is still in the resize window.
Normally HFS+ (the MacOSX file system) isn't case-sensitive, so having both
GtkQuartzWindow.h and gtkquartzwindow.h causes the latter to overwrite the
former during git pull, breaking the build.
