I came across a problem for a customer recently where they would launch the Service Manager 2012 console, and although the tasks bar (down the right hand side of the console) was visible there were no tasks displayed, also although the mouse was working they were unable to select anything within the console. The customer had a secondary test environment and using the same console to connect to this environment everything worked fine.
To resolve the problem you need to remove the console cache from “C:Users<username>AppDataLocalMicrosoftSystem Center Service Manager 2010”.
It’s worth noting that even though this is a 2012 environment the data is still stored under ‘System Center Service Manager 2010′. Also that AppData is a hidden folder.
The easiest thing to do is to close the console and rename the ‘System Center Service Manager 2010′ folder, re launch the console and a new folder structure will be built and the console will be back to its working self.