Vista - Converting WPF application XP to Vista

Hello,

I'm developing a WPF project. My OS was Windows XP Professional (x64) but I changed it to Windows Vista Ultimate x64. Now my project has a lot of problems about displaying menu items. They are inactive and cannot be activated by default, also canvases in menu items cannot be displayed. I just see the text. However, in other computers that have XP as OS, the project runs perfectly. Additionally, there are some problems about the parts that communicates with wifi interfaces and other drivers.

Have you ever experienced problems like these? What can cause them? I've read some articles that claims the codebase is identical in XP and Vista which is not completely true according to my experiences.

Thanks for reading.