title: Insert vertex inside a Graph
body: <p>I want to add a new vertex inside an existing graph.
  So I created a new cell and i'm attempted to reconnected my edge but my graph doesn't update (for the edges)</p>
  
  <p>This is my code : </p>
  
  <pre><code>    mxGraph graph = editor.getGraph();
  
  mxCell selectedElt = (mxCell) graph.getSelectionCell();
  Object cells[] = { selectedElt };
  
  if (selectedElt.isEdge()) {
      // cell is an edge, so we have source and target
      System.out.println("Source : " + selectedElt.getSource().getId());
      System.out.println("Target : " + selectedElt.getTarget().getId());
  } else {
      // edge before
      mxCell beforeEdge = (mxCell) selectedElt.getEdgeAt(0);
      // edge after
      mxCell afterEdge = (mxCell) selectedElt.getEdgeAt(1);
      // moving down the selected cell
      graph.moveCells(cells, 0, 50);
  
      // create a new vertex
      GraphStyle graphStyle = new GraphStyle(graph);
      mxCell cell = new mxCell("AAM",
              new mxGeometry(selectedElt.getGeometry().getX(), selectedElt.getGeometry().getY(), 80, 50),
              graphStyle.getCalculatorStyleName());
      cell.setVertex(true);
  
      beforeEdge.setTarget(cell);
      graph.insertEdge(graph.getDefaultParent(), "e33", "", cell, selectedElt);
  
      graph.addCell(cell);
      graph.repaint();
  }
  </code></pre>