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
}
		super.internalAdd(widget, parentElement, childElements);
	}
	private void virtualMaterializeItem(TreeItem treeItem) {
		if (treeItem.getData() != null) {
			
			return;
		}
		if (!(getContentProvider() instanceof ILazyTreeContentProvider)) {
			return;
		}
		ILazyTreeContentProvider lazyTreeContentProvider = (ILazyTreeContentProvider) getContentProvider();
		int index;
		Widget parent = treeItem.getParentItem();
		if (parent == null) {
			parent = treeItem.getParent();
		}
		Object parentElement = parent.getData();
		if (parentElement != null) {
			if (parent instanceof Tree) {
				index = ((Tree) parent).indexOf(treeItem);
			} else {
				index = ((TreeItem) parent).indexOf(treeItem);
			}
			lazyTreeContentProvider.updateElement(parentElement, index);
		}
	}
	/*
	 * (non-Javadoc)
	 *