#78 patcher right-click popup menu crash

[Pierre-Alexandre Pages]

under windows, there is a way to crash jMax when the
right-click popup menu is misused.

It is possible to select the last entry of the "new object"
popup menu, which is not a proper module, but instead,
is a tiny rectangular area which IS CLICKEABLE !

The first two times this area is clicked, jMax says :

"Adding New messbox object"

The third time, the context menu is crashed, and no more
objects could be added with it...

Worse, no new object could be created at all....