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
public void setExpandedElements(Object[] elements) {
		assertElementsNotNull(elements);
		CustomHashtable expandedElements = newHashtable(elements.length * 2 + 1);
		for (int i = 0; i < elements.length; ++i) {
			Object element = elements[i];
			
			
			
			
			internalExpand(element, false);
			expandedElements.put(element, element);
		}
		
		
		
		
		internalSetExpanded(expandedElements, getControl());
	}
	/**
	 * Sets which nodes are expanded in this viewer's tree. The given list
	 * contains the tree paths that are to be expanded; all other nodes are to
	 * be collapsed.
	 * <p>
	 * This method is typically used when restoring the interesting state of a
	 * viewer captured by an earlier call to <code>getExpandedTreePaths</code>.
	 * </p>
	 * 
	 * @param treePaths
	 *            the array of expanded tree paths
	 * @see #getExpandedTreePaths()