The Ctrl space does not set mark in Emacs

I installed Ubuntu 14.04 and use fvwm as the windows manager. The Ctrl+space does not set mark in Emacs. It seems that Ctrl+Space does nothing. I use Ctrl+Alt + F2 to go to the console, and Emacs works correctly there. If I use the Ubuntu default windows manager, emacs also works correctly. Does anyone have ideas what could be wrong? Thank you very much.

Solution 1:

I had this same issue and it looks like it's a problem with ibus. From the commandline run: ibus-setup

Under General::Next Input Method you should see <Control>space. Click on the three dots and change it to something else. Hit Apply and close out. ctrl-space should work in Emacs now.