This is a complicated bug.

Reproduce:
    o Create a widnow with a child 3x3 table
    o Add a widget to the top-left corner
    o Add a GtkFixed or GtkComboBoxEntry directly 
      under the other widget.
    o Click on the combo-box-entry
    o Click again on the combo-box-entry

Notice that every second click selects the top-left widget
of the GtkTable instead of the combo-box-entry.

The problem here (from what I understand) is that every second time the 
widget gets clicked (i.e. the time that we dont set the selection, the
time that we're supposed to forward the click to the actual object)
glade_widget_button_press() gets called twice instead of once;

the first time it gets called; glade_widget_retrieve_from_position ()
returns the correct gwidget and the second time it gets the wrong one.

from a closer look; it seems that glade_widget_button_press() was
called for an input only window created on the widget's behalf;

gtk_widget_translate_coordinates (); doesnt seem to like this; the
offset of the combo-box-entry inside the GtkTable is "dropped" and
the event->[x,y] are then calculated from the GtkTable's origin
instead.

This is a bug I was trying to fix (after implementing GtkFixed)
and never filed 'cause I though I'd just fix it and move on...
still havent fixed this sucker :-/