i installed Ubuntu 14.04 in VirtualBox. I have Qt Creator installed. I cannot use the Ctrl-Alt-Up and Ctrl-Alt-Down shortcuts (nothing happens). I know that the keyboard management really sucks in Ubuntu since the competing management tools (e.g. ccsm, gconf-editor, system settings, unity-tweak-tool etc etc.) all override each other and it is a big mess.
I remember having the same issue in 10.04 or 11.04. Is there a uberglobal setting that would override all the rest? Where to begin finding out who is eating up my keyboard shortcut?