Hi all, I am trying to adapt this example: http://www.vtk.org/Wiki/VTK/Examples/Cxx/Interaction/MoveAGlyph to interact with a vertex rather than a glyph. My attempt is here: http://www.vtk.org/Wiki/VTK/Examples/Cxx/Broken/Interaction/SelectAVertex Would someone mind taking a look at this to see why the "ghost glyph" never appears? Thanks, David