We are aware of UI clicking issues with Maya 2012 users running tablets that have been set to function in mouse mode instead of the default pen mode. At the moment we have only seen reports of this problem from Windows users.
While Maya 2011 did not have these tablet problems, Maya 2012 is running on a newer version of Qt which seems to have introduced this problem.
We are working on the issue with all the parties involved and hope to have it resolved in the near future. In the meantime if you are running into tablet issues in mouse mode please revert them back to pen mode in your Wacom tablet settings.