WPF Combobox bug when form allowtransparency=true

Question

I have found the following in WPF:

I have a form with AllowTransparency=true. Inside the form I put a Combobox. I add some items to the combobox.

I run this application and click on the combobox. At first it does not seem to appear at all. On closer inspection (after adding more items) I see that it is actually appearing behind the form. If I add enough items it become visible from behind the form.

If I just change AllowTransparency=false, then all is fine.

This looks like a bug in WPF (3.5 SP1).

Any one know of a workaround for this?

Answer 1

Go to https://connect.microsoft.com/dashboard/?wa=wsignin1.0

submit your feedback after searching @

https://connect.microsoft.com/VisualStudio

https://connect.microsoft.com/VisualStudio/feedback/CreateFeedbackForm.aspx?FeedbackFormConfigurationID=1160&FeedbackType=1

and mention steps to reproduce.

There was an update of 3.5sp1 but you could test,but I doubt

http://www.microsoft.com/downloads/details.aspx?familyid=6c095bba-6100-4ec9-9c54-6450b0212565&displaylang=en

Answer 2

AllowTransparency is slow and buggy and shouldn't be used - it's a great way to run into bug in various display drivers.

You can get almost anything you like without using AllowTrasparency, take a look at this post for examples:

http://blogs.msdn.com/wpfsdk/archive/2008/09/08/custom-window-chrome-in-wpf.aspx