stateChange will do an add grab if the selected length != 0 and the old selected length = 0, the problem is that if you are using JPopups in separate windows
and one of the popups is currently visible the old length will = 1 and the new length = 1, which means we won't install the MouseListeners on the new Frame and
clicking in the new frame will not cancel the popup as it should.
I have attached a test case of this, from a customer.
To reproduce it do the following (on solaris with click to activate):
right click on frame 1
right click on frame 2
right click on frame 1
at this point the popup won't show up and you need to do two more right clicks to get it to appear.