diagramCombo.addItemListener(this);
toolbar
.add(new RebuildGraphAction(this, Application.getInstance())
.buildButton());
toolbar.add(new SaveAsImageAction(this, Application.getInstance()).buildButton());
toolbar.addSeparator();
toolbar.add(new ZoomInAction(this, Application.getInstance()).buildButton());
toolbar.add(new ZoomOutAction(this, Application.getInstance()).buildButton());
toolbar.addSeparator();