@Override
  protected String getEdgeTip(final Edge edge) {
    final SingleGraph singleGraph = (SingleGraph) getGraph();

    if (CTooltipUpdater.isProximityNode(singleGraph, edge.source())) {
      return getNodeTip(edge.source());
    }

    if (CTooltipUpdater.isProximityNode(singleGraph, edge.target())) {
      return getNodeTip(edge.target());
    }

    final SingleDiffEdge diffEdge = singleGraph.getEdge(edge);
    final SingleDiffNode source = diffEdge.getSource();
    final SingleDiffNode target = diffEdge.getTarget();
    final ZyLabelContent sourceContent = source.getRealizer().getNodeContent();
    final ZyLabelContent targetContent = target.getRealizer().getNodeContent();

    return HtmlGenerator.getHtml(
        sourceContent, targetContent, Fonts.NORMAL_FONT.getName(), false, true);
  }
EditMode that handles node/edge tooltip generation for single graphs (primary/secondary).
java/ui/src/main/java/com/google/security/zynamics/bindiff/graph/editmode/SingleGraphEditMode.java