Bug 51653 [navigation] Quick Outline: Should also show interface members
I200402102000 We should consider showing the inherited members for interfaces at least when the target type is an interface itself.
org.eclipse.jdt.ui/ui/org/eclipse/jdt/internal/ui/text/JavaOutlineInformationControl.java
private boolean fIsFiltering= false;
		public 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) {