Click the red halo button for the flap closest to the right edge of the
world.  The menu pops up under the mouse cursor and if you don't hold
down the mouse button, then the menu item under the mouse cursor
receives the mouse up event.  Quick tests with other morphs similarly
placed revealed no problem; in those cases the menu popped up to the
left of the mouse cursor.

Image: 3.2gamma-4811
VM: Linux 3.2-4743 #1 [oss audio, xshm] from deb.

Ken Causey