The changes were previously being applied only when the combobox's edit
control lost focus notifying an end edit event.  In addition, the
selection of an item from the dropdown list should also cause the
changes to be applied. New functions were created to handle the
duplication in expected behaviour for these two events.

When run with the native richedit control the selection will be hidden
when focus is lost without the ES_NOHIDESEL style applied to the
richedit control.  This can be annoying in native windows when focus is
on a combobox in the toolbar, because it won't show what text will be
changed.  This patch adds the ES_NOHIDESEL style to be consistent with
native wordpad.

We report this for WINED3DFMT_D24S8, so there should be no reason
WINED3DFMT_D24X8 can't do it. Fixes a regression in 3DMark06.

Currently depth formats are handled separately from the other formats,
but depth formats can support things like filtering as well, so we
should check those caps as well.