[Source] tree view bug for Xj3D

[Don Brutzman]

have fixed the erroneous display problem of child node under a USE node. 
  didn't find a built-in method to test for USE status of a node, looked 
at string values instead to omit rendering of ghost children in scene tree.

also fixed Hide/Unhide button; added a partial fix for Show Only/Show 
All button, looks like it needs a render option in SceneGraphTraversal 
for this to be ppoossible.  thus changed the Show Only/Show All button 
to disabled until that functionality is available.

changes checked into NPS branch.

all the best, Don
-- 
Don Brutzman  Naval Postgraduate School, Code USW/Br       brutzman at nps.edu
Watkins 270,  MOVES Institute, Monterey CA 93943-5000 USA   +1.831.656.2149
X3D graphics, virtual worlds, navy robotics http://faculty.nps.edu/brutzman