Window Resizing

A have a window, on the left is a list and on the right an edit area.
I want to resize the window so that the right side slides over and hides the left so that
the part of the left side that is covered is completely hidden until the user expands the width again.

Is this possible? I thought the transparency button would do the trick but this has no effect on the Mac.


That sounds like a window splitter. (part of many classes - not free) (part of many plugins - not free) (free)

There are probably more window splitters available.