enthought/traitsui — pull request #78 by epatters (2012-09-12 20:07:05+00:00)
Title: BUG: Using 'visible_when' with Groups can leave ugly blank space.

See the comment in the diff for more information.

The referenced problematic code is:

https://github.com/enthought/traitsui/blob/master/traitsui/qt4/editor.py#L197