Strange stuff in Cubase 7

Hi guys !
So, I have this trouble with Cubase 7 - I create an instrument track, assign a VST instrument, open the drum editor or piano roll and start ‘drawing’ notes with my drumstick tool or pencil tool respectively… and hear nothing! Cubase used to play back the note I was inserting, but now it doesn’t. And, as far as I have noticed, my assigned VSTi doesn’t indicate receiving MIDI information when I do that. Yet, when I play my midi controller, or click keys/pads/etc in the VSTi interface window, or click the piano keys in the left side of the piano roll - it works, but when I manually insert notes with drumstick/pencil tool - it doesn’t. I checked the preferences, but failed to find anything that looks like addressing this issue. Any ideas? Thanks!