. When Alt Gr is pressed, then manually post WM_CHAR message on receiving a WM_KEYDOWN (manually translate and account for shift/control/caps-lock)
. Hook filter: suppress Alt Gr's (ie. RMENU's) fake LCONTROL messages
Also:
. Hook filter: allow Ctrl+Shift+Esc (for Task Manager)
. Keyboard: refactor only use accessor functions to get the Alt/Control/Shift state