In wxPython 2.8.7.1 under both Windows and Ubuntu, wx.DD_NEW_DIR_BUTTON
has a value of 0. This is one of the constants used to set the style
for the wx.DirDialog. I believe that the style is just a bitwise or'ing
of the various values. A value of 0 doesn't seem like it would have any
effect, which is what I am seeing.
Mark