void () { ThreadingAssertions.assertEventDispatchThread(); JScrollPane treePane = ScrollPaneFactory.createScrollPane(myTree); myPreviewSplitter = new OnePixelSplitter(false, 0.5f, 0.1f, 0.9f); myPreviewSplitter.setFirstComponent(treePane); myCentralPanel.add(myPreviewSplitter, BorderLayout.CENTER); updateUsagesContextPanels(); myCentralPanel.add(myAdditionalComponent, BorderLayout.SOUTH); myAdditionalComponent.add(myButtonPanel, BorderLayout.SOUTH); }