[vtkusers] Deleting unknown object

[David Doria]

I'm having trouble cleaning up memory leaks in some code. Here is an
example:

#include <vtkMutableUndirectedGraph.h>
#include <vtkBoostPrimMinimumSpanningTree.h>
#include <vtkTree.h>

#include <iostream>
#include <string>

int main(int argc, char *argv[])
{
  vtkMutableUndirectedGraph* G = vtkMutableUndirectedGraph::New();

    //create 3 vertices
  vtkIdType V1 = G->AddVertex();

  vtkBoostPrimMinimumSpanningTree* MinimumSpanningTreeFilter =
vtkBoostPrimMinimumSpanningTree::New();
  MinimumSpanningTreeFilter->SetOriginVertex(V1);
  MinimumSpanningTreeFilter->SetInput(G);

  vtkTree* MinimumSpanningTree = vtkTree::New();
  MinimumSpanningTree = MinimumSpanningTreeFilter->GetOutput();

  //cleanup
    //G->Delete(); //works ok
    //MinimumSpanningTreeFilter->Delete(); //works ok
  MinimumSpanningTree->Delete(); //deleting unknown object: vtkDataObject -
segfault

  return 0;
}