I've recently upgraded my gtx560ti to r9 270 and i think it's since then i started to getting that weird flickering... it happens only when the external preview is on, and only when i'm using CTRL+ALT for trims, shifting or sliding the events...
it flickers 2-3 times and then can move around, until i release the buttons, and then it flickers again for 2-3 times...
here's a little video so you might make some sense out of what i'm trying to say:
i had a fresh reinstall of the system (win 8.1 x64) after getting new gpu.
tried vegas 12 as well, and it's the same.
tried turning off gpu acceleration, optimize gpu display performance... still the same. going mental over it, as it's really really annoying.
any ideas?