Ubuntu Workspace Tab Key Stops Working Intermittently

I am having trouble with my ubuntu linux workspace... my 'Tab' key stops working inside the workspace from time to time and that without remedy. Like I cannot use Tab in a console or in a office document or anywhere really. Rebooting the image has no affect so far. The tab key in my windows image continues to work just fine and the problem seems to only occur in the Ubuntu linux images and only intermittently. I wanted to blame it on the Workspace client but again it works fine under my Windows image...