Bug 80473 [rulers][preferences] allow disabling of range indicator on left of java editor
org.eclipse.jdt.ui/ui/org/eclipse/jdt/internal/ui/javaeditor/JavaEditor.java
* @see org.eclipse.ui.IWindowListener#windowClosed(org.eclipse.ui.IWorkbenchWindow)
		 * @since 3.1
		 */
		public void windowClosed(IWorkbenchWindow window) {
		}
		/*
		 * @see org.eclipse.ui.IWindowListener#windowOpened(org.eclipse.ui.IWorkbenchWindow)
		 * @since 3.1
		 */
		public void windowOpened(IWorkbenchWindow window) {
		}
	}
	/**
	 * Runner that will toggle folding either instantly (if the editor is
	 * visible) or the next time it becomes visible. If a runner is started when
	 * there is already one registered, the registered one is canceled as
	 * toggling folding twice is a no-op.
	 * <p>
	 * The access to the fFoldingRunner field is not thread-safe, it is assumed
	 * that <code>runWhenNextVisible</code> is only called from the UI thread.
	 * </p>
	 *
	 * @since 3.1
	 */
	private final class ToggleFoldingRunner implements IPartListener2 {
		/**
		 * The workbench page we registered the part listener with, or
		 * <code>null</code>.
		 */
		private IWorkbenchPage fPage;