stop render on windows7

Hi,

When I restore from lock screen on windows7, it didn't render until restart the program.
I try to get last error code after EndDraw() but it return 0 without any exception.
I also try another library SharpDX sample (BitmapApp), it seens work.
Do you have any idea about this?

Reproduce the rendering failure by restoring from the lock screen on Windows 7, then compare the behavior with the SharpDX BitmapApp sample mentioned in the issue. Done means rendering resumes after unlock without restarting the program and the relevant failure can be identified despite EndDraw() returning 0.

Written by the indexing model from the issue text.