Reply To: RE: Can't write letter "ć".
It is because, Windows handle Alt+Ctrl and RAlt in the same way.
In past keyborad send the same key code for both Alt's, so MS make this workaround.
So, when You use PL-programmer keyboard, You can't use any Alt+Ctrl shortcut's.
I don't know how to change shortcuts in SIM (Is it possible for users?), but this is the reason.