[vtkusers] vtkCommand::LeftButtonReleaseEvent does not work

[curator]

Hi all (for the last time today),

recently, I caught my events by MousePress events as follows:
vtkEventQtSlotConnect *t_connections = vtkEventQtSlotConnect::New();
     t_connections->Connect( 
m_VTKWidget->GetRenderWindow()->GetInteractor(),
                               vtkCommand::MouseMoveEvent,
                               this,
                               SLOT(onCmdMouseMotion(vtkObject*)));
     t_connections->Connect( 
m_VTKWidget->GetRenderWindow()->GetInteractor(),
                               vtkCommand::LeftButtonPressEvent,
                               this,
SLOT(onCmdMouseLeftPress(vtkObject*)));

Both work perfectly, but unfortunatly I want to do sth, only then I 
"click" or "doubleclick" on an item rather than rotate the scene.

Unfortunaly, I didnt found something like vtkCommand::DoubleClickEvent, 
so I decided to add a new trigger:

t_connections->Connect( m_VTKWidget->GetRenderWindow()->GetInteractor(),
                               vtkCommand::LeftButtonReleaseEvent,
                               this,
SLOT(onCmdMouseLeftRelease(vtkObject*)));

and simply check if the mouse has not moved (except some eps) since 
button press. The problem is, that this last slot does not trigger, 
because onCmdMouseLeftRelease() is never called. What is the difference 
between the first two and the last call?

regards,
curator