How to identify a keymap conflict? I can't access the Clipping Border command (Alt+B) with my standard Blender setup. When I load factory settings everything works okay, so I presume there must be an addon that conflicts with this command (I realize I could be wrong).

Is there a way to find the conflicting addon except for turning all of them off and then load one by one?
Go to File > User Preferences > Input, set the dropdown menu next to the search field to Key-Binding and enter AltB. It should list all operators bound to a key. It includes addon keybindings.



Addons can also capture events in modal operators, but it's really rare that they consume certain events and pass on the rest. So it would be pretty obvious that there's something running in the background, because a lot of actions wouldn't work.