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
Assert.isTrue(tis[i].getData() == null,
									"Second or later child is non -null");
						}
						tis[i].dispose();
					}
				}
				Object d = widget.getData();
				if (d != null) {
					Object parentElement = d;
					Object[] children;
					if (isTreePathContentProvider() && widget instanceof Item) {
						TreePath path = getTreePathFromItem((Item) widget);
						children = getSortedChildren(path);
					} else {
						children = getSortedChildren(parentElement);
					}
					for (int i = 0; i < children.length; i++) {
						createTreeItem(widget, children[i], -1);
					}
				}
			}
		});
	}
	/**
	 * Creates a single item for the given parent and synchronizes it with the
	 * given element.
	 * 
	 * @param parent
	 *            the parent widget
	 * @param element