[PyCrust] making the popup list height variable

[Kevin A. <al...@se...>]

If the window height is too small, you should probably change the size of
the drop down menu, which currently can go off the bottom of the window. On
my default shell window size
   'shellPosition':(50, 600),
   'shellSize':(700, 200),

The 6 line menu probably needs to be 4 instead and I could see wanting it to
be a bit bigger if I had a taller shell window.

ka