COMSOL 4.4 under Ubuntu 12.04: problem with command keys

Using COMSOL Desktop under Ubuntu 12.04

Certain keys on the keyboard are directly linked to menu commands. For instance, when I hit the 's' key in a text field, COMSOL automatically does the "Save" command, or when I hit the 'o' key in a text field, COMSOL pops up the "Open" dialog box.

I'm relatively familiar with COMSOL, but have just started using it under Ubuntu, so maybe this is an obvious problem and I'm missing something...

Thanks for your help,

John