Photoshop :: Open Multiple Raw Files In ACR Hosted By CS5.1?

I used to highlight multiple raw files in Bridge and just press Enter (being the equivalent to File -> Open) and the images would all open together in one ACR interface with the filmstrip down the side.  Now, however, one file opens and if I hit cancel or done, the second image THEN opens, and so on and so forth.  If instead of pressing Enter I choose File -> Open in Camera Raw or I right-click and Open in Camera Raw, it works fine and does what I want (or if I click the aperture symbol on the toolbar at the top). 
 
The worst part is that it worked fine until I uninstalled CS5.1.  I had CS5.1 no problem, then installed CS6/CC alongside it.  I got eveything working how I wanted in CS6/CC and then uninstalled CS5.1.  I may be wrong on the exact timing of the problem and therefore it may be a Red Herring, but it seems fairly close together when this started.
 
Notes:  There is no expansion bar on the left of ACR that is just hiding the filmstrip.  Which is consistant with the fact that the second image does in fact open after I close the first.  So they are clearly being treated as seperate open actions.  Also, in Bridge, Edit -> Preferences -> General: 'Double-click Edits Camera Raw Settings in Bridge', ticked or unticked makes no difference.  Also in Photoshop, Edit - Preferences -> File Handling: 'Prefer Adobe Camera Raw for Supported Raw Files', ticked or unticked makes no difference.
 
I have also tried changing the above mentioned options, closing PS and Bridge so the preferences file is updates, changing them back to how I want and closing so the preferences file is updated and I get the same results.