[0.12.2]Game freezes when minimized or otherwise interrupted

[Madara Uchiha]

Attached are both my log files (current and previous). The chain of events is:

1. I am running factorio from the update patches since 0.11 and am currently on latest 0.12.2, and am running Ubuntu 15.04.
2. While in-game, have not tried on menus
3. Press Alt, that brings up the Ubuntu command menu. OR
   Use hot corners to "show all active windows". OR
   Press ALT+TAB to switch windows (even if returning directly to Factorio without any switching)
4. Factorio freezes, music keeps playing, but keyboard is not responsive. Can't ESC into the menu, can't ALT+F4. Had to run

   Code: Select all

   killall factorio

   from terminal to terminate Factorio.

[Oxyd]

What graphics card do you have?