GTK excewption raised

[ikorot earthlink net]

Hi, ALL,
In the GtkComboBox documentation I see this:

[quote]
The "popdown" signal
gboolean            user_function                      (GtkComboBox *button,
                                                        gpointer     user_data)      : Run Last / ActionThe ::popdown signal is a keybinding signal which gets emitted to popdown the combo box list. 

The default bindings for this signal are Alt+Up and Escape.


button :
 the object which received the signal  
user_data :
 user data set when the signal handler was connected. 

Since 2.12


--------------------------------------------------------------------------------

The "popup" signal
void                user_function                      (GtkComboBox *widget,
                                                        gpointer     user_data)      : Run Last / ActionThe ::popup signal is a keybinding signal which gets emitted to popup the combo box list. 

The default binding for this signal is Alt+Down.


widget :
 the object that received the signal  
user_data :
 user data set when the signal handler was connected. 

Since 2.12
[/quote]

I want to se those notification events to dynamically change the content
of the combo box.

So, for the "popdown" handler, I am writing (pseudo-code):

combo->Clear();
combo->Append( "Text1" );
combo->Append( "Text2" );
combo->Append( "Text3" );

On the "popup" event, I have (pseudo-code):

combo->Clear();
combo->Append( "Select String" );

I have 2 problems.

1. If the original combobox has the string and the string is selected, then
the dropdown button is covered by dropdown list.

2. If I select the string, the list disapper and the "popup" event is fired,
however, I see the GTK exception that is raised.

I'm using GTK+ 2.14.7 on Gentoo Linux, and working with the wxWidget6s/wxGTK
library.

On of the core wxGTK developers suggested that current GTK+ implementation
is doing something and does not expect the content of the combobox to be changed
on those 2 events.

So, here are my questions:
1. Is there a plan to make those 2 events work the same as in Windows WM_CBDROPDOWN
and WM_CBPOPUP?

2. What GTK+ does during the processing of those 2 events that prevents programmer to change 
the content of the combo box?

Thank you.