There is a serious problem with this fix on Ubuntu 14.04 using the default Unity compositor.
When I am running Minecraft in fullscreen and I press my volume up-down / mute or PrtScrn (not the Minecraft F2 screenshot key), Minecraft will leave fullscreen mode and minimize to the launcher icon to show the Notify OSD message box or screenshot dialogue.
All I can see is my Ubuntu desktop, it is now impossible to return to Minecraft when I try to alt-tab or click on the launcher icon. Minecraft is still running in the background (I can hear the music), but the only option is to quit, or sometimes when playing in a minecraft world I have to kill the process.

Previous versions pre 14w34d, would leave fullscreen, enter windowed mode, show the notification or dialogue, then I can press F11 to return to fullscreen mode.

Would be better if when the volume / mute keys did not exit fullscreen mode, and show the OSD notification as normal. The PrtScn button for screenshots would cause minecraft to enter windowed mode, show the screenshot dialogue, then allow me to select minecraft and F11 to return to fullscreen.

Note:
I reported this in
Minecraft / MC-55045 - Race condition in linux fullscreen toggle.
But I guess that that issue is resolved, and this issue has been ignored.