Mouse strange interaction

Hi All,
I have a strange problem on MSFS or maybe not!.
All the cessna aircraft exhibit this effect:-
all the radio & navigation displays are flashing UNTIL I press & hold the right mouse button, then the flashing stops. On release, back comes the flashing, oh by the way it also affects the cockpit lights on/off.
anyone have any idea what is causing this??
SJ

When I hold right mouse button the trim wheel rotate full backward :rofl::rofl::rofl:
I stopped using rmb.:sob: