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 void disassociateChildren(Item item) {
		Item[] items = getChildren(item);
		for (int i = 0; i < items.length; i++) {
			if (items[i].getData() != null) {
				disassociate(items[i]);
			}
		}
	}
	
	protected Widget doFindInputItem(Object element) {
		
		Object root = getRoot();
		if (root == null) {
			return null;
		}
		if (equals(root, element)) {
			return getControl();
		}
		return null;
	}
	
	protected Widget doFindItem(Object element) {
		
		Object root = getRoot();
		if (root == null) {
			return null;
		}
		Item[] items = getChildren(getControl());
		if (items != null) {
			for (int i = 0; i < items.length; i++) {