[gtkmm] TreeView and callbacks

[steve przepiora org <steve przepiora org>]

I am having a problem with some gtkmm callbacks and was wondering if someone 
could help me out. I have a TreeView and wish to attach to the 
signal_button_press but it doesn't seem to be calling the callback.

I am attaching the callback with:
m_TreeView.signal_button_press_event().connect(SigC::slot(*this, 
&ProjectView::on_cell_button_press_event));

and the callback is defined as:
bool ProjectView::on_cell_button_press_event (GdkEventButton* event)

It appears to not call the callback at all.

Thanks,
Steve