Understanding why two gui windows displayed.

[Timothy Ward <gtwa001 gmail com>]

Basically a GUI is built with a clutter stage with numerous clutter
actors which is then embedded into a gtk3 window but now displays two
separate GUI windows on later gnome3 shells (from 3.10).
If someone could explain why the above is happening so I can resolve
the issue. The stage used to have all actors displayed but now the
widgets are basically split into gtk3 and clutter actors in there own
windows. 

The code is on https://github.com/gitsop01/sbmanager/ if anybody wants
to have a look.