I reported this problem years ago and nothing has been done. I guess not enough people use multiple monitor setups.
I've got 4 screens in a 2x2 setup - the left 2 screens are off one video card, and the right 2 off another card. The bottom of each card is the primary display (DV) and DOES display right-click options, but the top screen doesn't.
A workaround (though still annoying) - you CAN'T right-click on a handle, but you CAN click and then press the right-click button on the keyboard and the context-sensitive menu then pops up. It's quicker than having to move to the other screen.
Hope this helps you,
...and then press the right-click button on the keyboard...