XnView Software

Hello everybody,
I use the xnview version 2.43 with windows 10. Unfortunately, I do not get everything displayed on the "Adjust Brightness / Contrast / Gamma" window (see picture). Does anyone know this error and can help me?
Greetings Rudi
P.S. Sry for my bad english (google-translator)

please check this topic

Thanks! Thats help me a lot!
Thank you very much!