CCombo not working properly

[AlexCl]

Hi everyone,
first of all: I tried to solve the problem on my own for weeks and used google and several forum searches but didn't find an answer so I hope to find some help by posting my problem...

My problem is that CCombos don't seem to be working in my apps. I used SWTDesigner to build my GUI but when I try to use CCombos I cannot select anything. I can type into the textfield and when I click on the arrow I can see the CCombo-Items but I cannot select anything, the items are not even highlighted when I move the cursor over them the I also cannot scroll the itemlist. When I use a "normal" Combo-widget I do not have any of the problems explained.

I would be very happy if anyone could help me finding the reason for this...
Thanks,
Alex.

PS: When I use the preview function of SWTDesigner the CCombos seem to work properly but but when I try run my app.