if (elementToSelect.eResource() == null)
  return;

for (IEditorReference reference : PlatformUI.getWorkbench().getActiveWorkbenchWindow().getActivePage().getEditorReferences())
  if (reference.getPartName().equals(nameToLookAt))
    editorReference = reference;
		
if (editorReference == null)
  return;
		
IEditorPart editorPart = editorReference.getEditor(true);
		
if (! (editorPart instanceof xxxDiagramEditor) )
  return;
		
List editParts = yyyDiagramEditor.getDiagramGraphicalViewer().findEditPartsForElement(EMFCoreUtil.getProxyID(elementToSelect), xxxEditPart.class);
		
IGraphicalEditPart editPart = (IGraphicalEditPart)editParts.get(0);
yyyDiagramEditor.getDiagramGraphicalViewer().select(editPart);
yyyDiagramEditor.getDiagramGraphicalViewer().reveal(editPart);