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
* accurately reflect the model. This method only affects the viewer, not
	 * the model. Note that there is another method for efficiently processing
	 * the simultaneous addition of multiple elements.
	 * </p>
	 * 
	 * @param parentElementOrTreePath
	 *            the parent element or path
	 * @param childElement
	 *            the child element
	 */
	public void add(Object parentElementOrTreePath, Object childElement) {
		add(parentElementOrTreePath, new Object[] { childElement });
	}
	/**
	 * Adds the given SWT selection listener to the given SWT control.
	 * 
	 * @param control
	 *            the SWT control
	 * @param listener
	 *            the SWT selection listener
	 * @deprecated
	 */
	protected void addSelectionListener(Control control,
			SelectionListener listener) {
		
	}
	/**
	 * Adds a listener for expand and collapse events in this viewer. Has no
	 * effect if an identical listener is already registered.
	 *