Bug Unity Freezes when another active OpenGL process is open

This is a bit of an Odd one.

So i had a few other tabs open when i found out that if i enabled OpenGL on applications other than Unity it would cause unity to stop updating the screen and show a freeze frame of the UI before it froze, and if i disable openGL on the other software, unity starts working again. I'm using Ubuntu 15.10, on editor version 2015121801

 

Try the newest version:
http://download.unity3d.com/download_unity/linux/unity-editor-5.3.1f1+20160106_amd64.deb

It works a lot better than version that You are using.