[vtkusers] combine custom and regular VTK interaction in the widgets derived from vtkAbstractWidget

[kshivann at engineering.uiowa.edu]

hi all,
     i am trying to combine custom interation with the regular vtk  
interactions. for e.g., if i set a call back method for left button  
press event,

   this->CallbackMapper->SetCallbackMethod(
             vtkCommand::LeftButtonPressEvent,
             vtkEvent::NoModifier, 0, 1, NULL,
		vtkMimxUnstructuredGridWidget::LeftMouseButtonDown,
			this, vtkMimxUnstructuredGridWidget::LeftButtonDownCallback)

only the custom interaction takes place. the code for function  
LeftButtonDownCallback is as follows,

void  
vtkMimxUnstructuredGridWidget::LeftButtonDownCallback(vtkAbstractWidget  
*w)
{
vtkMimxUnstructuredGridWidget *self =  
reinterpret_cast<vtkMimxUnstructuredGridWidget*>(w);
{CUSTOM INTERACTION}
	self->EventCallbackCommand->SetAbortFlag(1);
	self->StartInteraction();
	self->InvokeEvent(vtkCommand::StartInteractionEvent,NULL);
	self->Interactor->Render();
}

custom interaction is activated only if for e.g., a face or a point is  
picked else the regular vtk interactions should take precedence in the  
same function. Any help is greatly appreciated.

thanks

kiran