I used to be able to pick multiple MEP electrical devices (lights, receptacles, etc) and then double click one and have the properties pallete open. In 2012 it now pops up the quick properties dialog and says it does not support that object type.
I have the Quick Properties panel off when I double click.
It worked in 2011 MEP.
I can go to the properties pallete and edit them with multiple selected, it just does not open it up automatically like it did before.