Not getting combo box change event

I have a popup_editor that contains, among other things, a combo box.  I want to update the display when the combo box's selected value is changed.

I am completely failing to get the OnChange event, however.  I have tried to break in it, and the breakpoint never fires.  I have put a feedback message as first thing in the handler routine and I never get the message.

Below is a picture of my dev environment, some help on where my event could be going or why itys not firing would be really appreciated.

Never mind figured it out.  It was a problem elsewhere that was cuasing a silent exception