Hi,
I ran into a strange issue where "fn_key -- F4" combination on my hp laptop to extend the screen would stop working once I have a wpf application running. This happens even when I create an empty app -- as soon as I run it, I can't extend my desktop to a second monitor.
Thanks!
Sounds like an issue with your video driver. What kind of video card is it? Are you running the latest drivers from the vendor?
The problem was a driver issue (as Drew mentioned above).
To diagnose an issue like this, please follow the instructions from the MSDN article (http://msdn.microsoft.com/en-us/library/aa970912.aspx) on how to disable hardware acceleration and render everything in software.
Provided your issue is similar to what I have experienced, you will be able to single out the problem by adding the necessary registry key from the article.