Bug 62909 [performance] quick outline takes forever to show up
org.eclipse.jdt.ui/ui/org/eclipse/jdt/internal/ui/text/JavaOutlineInformationControl.java
private boolean fIsFiltering= false;
		private OutlineTreeViewer(Tree tree) {
			super(tree);
		}
		
		/**
		 * {@inheritDoc}
		 */
		protected Object[] getFilteredChildren(Object parent) {
			Object[] result = getRawChildren(parent);
			int unfilteredChildren= result.length;
			ViewerFilter[] filters = getFilters();
			if (filters != null) {
				for (int i= 0; i < filters.length; i++)
					result = filters[i].filter(this, parent, result);
			}
			fIsFiltering= unfilteredChildren != result.length;
			return result;
		}
		
		/**
		 * {@inheritDoc}
		 */
		protected void internalExpandToLevel(Widget node, int level) {
			if (!fIsFiltering && node instanceof Item) {
				Item i= (Item) node;