Ubuntu – Making youtube fullscreen will freeze Unity (the whole desktop)

I never had this problem until today. When I watch a youtube video everything is fine, until I make the video fullscreen. It actually continues to play perfectly when fullscreen, but when I then exit fullscreen my sidebar and topbar are gone, and the screen is just frozen. Also my cursor is gone. It does seem to respond to ALT-F4, but it takes about 15 seconds to even close the window, and after that everything is unusable (basically frozen). What's strange though, when I re-enter fullscreen after exiting (and unity being frozen) the video plays perfectly still.

For now my workaround is opening tty1 and executing pkill -u username which logs off the user. I have looked at /var/log/syslog but it seems to be empty.

Is this freezing a common problem, if not, how can I make steps to fix this?

EDIT with specs:

I'm on a simple Samsung laptop with:
Ubuntu 14.10 64-bit,
Intel® Core™ i5-3210M,
Intel® Ivybridge Mobile (So integrated intel hd graphics 4000),
8GB ram. I don't think i've ever changed my video drivers, but it's reported as i915.
Ubuntu is up to date, and my browser is Chrome 40.0.2214.91 (64-bit). (Will test out now with firefox, but already posting this because my pc might freeze again)

EDIT 2: It doesn't freeze on Firefox. Will try reinstalling chrome now…
EDIT 3: Reinstalling chrome didn't help. Will try chrome 32-bit too now…