Several times I discovered a problem with Debug Bar switching on/off on the frontpage. On some installations it works fine on other it fails. Switching on/off in the backend seems to work.
Now I've tested Debug Bar on a resetted clean wp3.3.1 installation and theme TwentyEleven with all other plugins disabled. When I toggle Debug Bar no output field is displayed although it is contained in the HTML page (can be toggled on with Firebug). When toggling fails, the URI is extended with a '#'.
Original call: http://www.example.com/product-page/
After toggling fails: http://www.example.com/product-page/#
Also I found a conflict with the commercial plugin LoopBuddy. The meta boxes on the options page of this plugin could not be expanded/collapsed and the save button disappeared as long as Debug Bar was active. The reason must not be found at Debug Bar, but there may be other plugins which could have the same strange behaviour.