When I click the little gear / power icon at the top right of my left monitor, I see this (without blur -- that's just an artefact of me pressing PrintScreen and then having the menu try to dismiss while the image is being captured):
Of course, in my desktop setup the two monitors are not completely side-by-side and so this is somewhat annoying. I would prefer if context menus (opened by mouse actions) opened on the same monitor as my mouse. This of course occurs correctly on the right monitor.
This is with Ubuntu 14.04 (and with a Geforce GTX 960 + latest drivers [346.72], in case that is relevant)