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
private static final String VIRTUAL_DISPOSE_KEY = Policy.JFACE
			+ ".DISPOSE_LISTENER"; 
	/**
	 * Internal tree viewer implementation.
	 */
	private TreeEditorImpl treeViewerImpl;
	/**
	 * This viewer's control.
	 */
	private Tree tree;