Bug 38569 Override/Implement Methods dialog should expand first element in viewer.
The treeviewer in the Override/Implement dialog isn't automatically revelaing the first element in the list, but it should to be consistent with other dialogs.
org.eclipse.jdt.ui/ui/org/eclipse/jdt/ui/actions/AddDelegateMethodsAction.java
private static final String DIALOG_TITLE = ActionMessages.getString("AddDelegateMethodsAction.error.title"); 
	private CompilationUnitEditor fEditor;	
	/**
	 * Creates a new <code>AddDelegateMethodsAction</code>. The action requires
	 * that the selection provided by the site's selection provider is of type <code>
	 * org.eclipse.jface.viewers.IStructuredSelection</code>.
	 * 
	 * @param site the site providing context information for this action
	 */
	public AddDelegateMethodsAction(IWorkbenchSite site) {
		super(site);
		setText(ActionMessages.getString("AddDelegateMethodsAction.label")); 
		setDescription(ActionMessages.getString("AddDelegateMethodsAction.description")); 
		setToolTipText(ActionMessages.getString("AddDelegateMethodsAction.tooltip")); 
		WorkbenchHelp.setHelp(this, IJavaHelpContextIds.ADD_DELEGATE_METHODS_ACTION);
	}
	/**
	 * Note: This constructor is for internal use only. Clients should not call this constructor.
	 */
	public AddDelegateMethodsAction(CompilationUnitEditor editor) {
		this(editor.getEditorSite());
		fEditor = editor;
		setEnabled(SelectionConverter.getInputAsCompilationUnit(editor) != null);
	}
	
	/* (non-Javadoc)
	 * Method declared on SelectionDispatchAction
	 */
	public void selectionChanged(IStructuredSelection selection) {