How to see, which key is pressed, as seen by unity window manager?

After a system crash, the shortcuts I use for switching the workplaces with Mod_3 modifier (e.g. Mod_3 + Left to switch workplace left) ceased to work.

I use the following .Xmodmap script:

remove control = Control_R
clear mod3
add mod3 = Control_R

loaded with xmodmap .Xmodmap.

The Control_R key is working properly, as reported by xev. But xev is too much "low level" - it shows physical keys pressed.

I need something that allow me to verify that pressing "right control" together with "left arrow" is seen as Mod3+Left to the unity.

Something, that could replace the partially broken All Settings->Keyboard window (it was never compatible with the Mod3 compose key).

update:

It appeared, that the shortucts were disabled because the Desktop Wall compiz plugin was disabled. Enabling it brought back the functionality. Nevertheless the question stands valid and unanswered.