Please describe the problem:
GtkTreeViewColumn offers a callback, via set_cell_data_func, that is called to set up a combo box for every list/tree entry. Setting a model (via g_object_set) and trying to edit the list entry results in the combobox flashing and becoming unresponsive.

Steps to reproduce:
1. Compile and run the sample program


Actual results:
Combobox (and application) is unresponsive. User cannot select a combobox entry.

Expected results:
Combobox functions normally, like when the model is set without a callback.

Does this happen every time?
Yes

Other information: