XF5/Android: BackgroundColor changes after KeyEvent

Question

In my App I am detecting KeyEvents with real Hardware Keyboards or Strokes that come from a Bluetooth-Scanner-Device. I am not using any Entries for that. The page receives every KeyEvent and puts a String together until it receives an "Enter". That works fine. Here is my Problem: I am using a ContentPage with a white BackgroundColor. When I press a Key the whole Page gets "grayish" like it has not the focus anymore and that looks not nice. Is there any chance to find an option to solve that ? I'm afraid I'm once again the only person who has such a problem at all, but hope dies last....