On-screen Keyboard wrongly painted when switching from extended to standard

reactos-bootcd-0.4.15-dev-142-gc276681-x86-gcc-lin-dbg

Painted with the background icons, which then "follows" standard OSK when moved

Steps to reproduce :

• Set screen resolution to 800x600
• Start OSK as "Enhanced Keyboard" (place it on the leftmost border if not done automatically, above Desktop icons)
• Set to Standard Keyboard
• Keyboard is now painted with Icons over it
• Move keyboard