I can confirm there seems to have been a change in behavior between 2011 & 2011.5 in this respect. This is probably due to the incorporation of the ViewCube, although disabling the ViewCube doesn't change it back. The documented behavior AFAIK always was defined as followed
Quote:
When an SRT manipulator is active, you can open a context menu by right-clicking on the manipulator in a 3D view
(the SI2011SP1 User's Guide), which hasn't changed. Seems to me right-clicking outside of the manipulator to get to the context menu could just have been a side-effect, not so much an intended feature. I could however be wrong (and often am...)
Apparently I have fallen into the age-old trap of "has been answered elsewhere also already"...