Created attachment 693402 [details]
reproducer that needs the combobox.glade file in the same directory

Description of problem:
When using GtkCombobox with GtkEntry and GtkEntryCompletion for it loaded from the .glade file, the completion is not rendered correctly (doesn't appear).


Version-Release number of selected component (if applicable):
gtk3-3.6.2-1
glade3-3.8.3-1

works with:
gtk3-3.4.4-1.fc17.x86_64
glade-3.14.1-1.fc18.x86_64

How reproducible:
100 %

Steps to Reproduce:
1. run the attached reproducer (combobox_test.py)
2. try to type 'f' to the upper combobox's entry
  
Actual results:
only some "shadow" appears

Expected results:
completion appears

Additional info:
combobox_noglade.py (attached) works as expected (try to type 'a')