fix display of backlash comp graph on wxGTK by using a wxStaticBitmap, not a disabled wxBitmapButton
fix display of backlash comp graph on wxGTK by using a wxStaticBitmap, not a disabled wxBitmapButton

OpenPHDGuiding/phd2,OpenPHDGuiding/phd2,OpenPHDGuiding/phd2,OpenPHDGuiding/phd2,OpenPHDGuiding/phd2,OpenPHDGuiding/phd2