WPF application black after locking windows and resume to desktop

Question

We have a small problem with our .net 4.0 wpf application. If the user locks his screen (windows) and a few seconds later unlock the screen (resume to the work), the application looks like this:

The user can not click on any control or do some thing. The curious thing is, that it only appears if the user is on special tabs, where we use BeginInvoke and work a lot with threading. I could not find any thing about this bug, besides that BeginInvoke can create those problems.

I also could not find any thing in the windows logs.

EDIT

I use multimonitor, if my application is black, removing the monitor cable an reconnecting it, the application continues to work.

Answer 1

The problem only seems to appear when using the wpf DataGrid. Switching from thsi grid to Telerik-Grid solve the problem, but i could not figure out which part cause the problem.