I can confirm this behaviour on a fresh install of 14.04 - although "Window Spread" doesn't seem to trigger it in my setup. It seems to just happen at certain points, and closing the window and reopening solves the issue temporarily.
I can confirm this behaviour on a fresh install of 14.04 - although "Window Spread" doesn't seem to trigger it in my setup. It seems to just happen at certain points, and closing the window and reopening solves the issue temporarily.