It only happens when I click somewhere - regardless where.
The last entry in the log says
"..\..\src\msw\window.cpp(591): 'SetFocus' failed with error 0x00000057 (falscher Parameter.)."
The previous are like this: "Using Framebuffer with texture."
At the beginning there are some graphic errors, but they are just because I didn't put in the new files into the second screen. Which doesn't matter because she doesn't get to it anyway
Edit: Changed the settings to try if the second screen works. It does. I don't know why, because I did the exact same with the first screen O.o