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/TreeViewer.java
* 
	 * <strong>EXPERIMENTAL</strong>. This class or interface has been added as
	 * part of a work in progress. There is no guarantee that this API will
	 * remain unchanged during the 3.2 release cycle. Please do not use this API
	 * without consulting with the Platform/UI team.
	 * </p>
	 * 
	 * @since 3.2
	 */
	public void replace(Object parent, int index, Object element) {
		if (parent.equals(getInput())) {
			if (index < tree.getItemCount()) {
				updateItem(tree.getItem(index), element);
			}
		} else {
			Widget[] parentItems = findItems(parent);
			for (int i = 0; i < parentItems.length; i++) {
				TreeItem parentItem = (TreeItem) parentItems[i];
				if (index < parentItem.getItemCount()) {
					updateItem(parentItem.getItem(index), element);
				}
			}
		}
	}
	public boolean isExpandable(Object element) {
		if (getContentProvider() instanceof ILazyTreeContentProvider) {
			TreeItem treeItem = (TreeItem) internalExpand(element, false);
			if (treeItem == null) {
				return false;
			}