title: set-mark-command not working emacs with C-SPC
body: <p>I am not able to set the <code>mark</code> at the current point by <code>C-SPC</code> (both when <code>emacs</code> loads the <code>init</code> file and when it doesn't). However, when I do <code>M-x set-mark-command</code>, the mark is well set and I am able to select the region by moving the cursor. When I do <code>M-x apropos set-mark-command</code>, it shows two bindings <code>C-@</code> and <code>C-SPC</code>, but only the first one works. Any suggestions will be appreciated.
  I am running emacs 24.3 on a GUI on Kubuntu 14.04.</p>