The catalyst for this RFE is bug 4425878 : popup menu disappears off screen when placed near the edge of screen.

Looking at other GUIs (win32, CDE), it's damn near impossible to get a contextual menu to disappear off the edge of the screen. It's actually quite easy to do with Swing. While it is true that client code could calculate the mouse's proximity to the edge of the screen and adjust the placement of a popupmenu accordingly, it's safe to assume that most Swing developers are interested in not having their menus sprawl off screen. Note that we already do this for Swing menus in a menu bar, as well as ComboBoxes.

Perhaps this would require new API, perhaps not.