Going into F11 fullscreen and tapping Alt-Tab or Super (Window) key to return to desktop caused Minecraft to glitch, flashed semi-transparently. It looked like it's showing alternate frame page-flipping on desktop transparent layer or something like that. Minecraft blocked access to the desktop. Alt-Tab to Minecraft widget did not return focus to minecraft. Could not therefore exit fullscreen and it remained in the glitchy state. I was forced to reset the computer manually.
Environment
Ubuntu 14.10 with Unity gtk3, oracle java 1.8.0_u25 -Xmx4G argument, Intel 4440 x86-64, integrated Intel video chipset, 16gb ddr3 ram
Please force a crash by pressing F3 + C for 10 seconds while in-game and attach the crash report (
[minecraft/crash-reports/crash-<DATE>-client.txt|http://hopper.minecraft.net/help/finding-minecraft-data-folder]) here.