Bug 158778 [Viewers] request for remove(parent, index) API on tree viewer
3.3 It would be helpful to have a 'remove(Object parent, int index)' method on the tree viewer to complement that 'replace(...)' and 'setChildCount(...)' APIs. The debug platform requires such a method to implement filtering in virtual tree views. Rather than performing a 'replace/remove' based on elements, the content provider can make one atomic call to remove an element at a specific index.
bundles/org.eclipse.jface/src/org/eclipse/jface/viewers/AbstractTreeViewer.java
private Object[] filter(Object parentElementOrTreePath, Object[] elements) {
		ViewerFilter[] filters = getFilters();
		if (filters != null) {
			ArrayList filtered = new ArrayList(elements.length);
			for (int i = 0; i < elements.length; i++) {
				boolean add = true;
				for (int j = 0; j < filters.length; j++) {
					add = filters[j].select(this, parentElementOrTreePath,
							elements[i]);
					if (!add) {
						break;
					}
				}
				if (add) {
					filtered.add(elements[i]);
				}
			}
			return filtered.toArray();
		}
		return elements;
	}
	/**
	 * Create the new elements in the parent widget. If the child already exists
	 * do nothing.
	 * 
	 * @param widget
	 * @param elements
	 *            Sorted list of elements to add.
	 */
	private void createAddedElements(Widget widget, Object[] elements) {