Bug 38782 TreeViewer add calls a refresh
Our implementation of TreeViewer.add is naive and can all a refresh of the entire tree. It should be more like TableViewer.
bundles/org.eclipse.jface/src/org/eclipse/jface/viewers/AbstractTreeViewer.java
Object element;
		Item item;
		boolean exception = false;
		public void run() {
			if (exception)
				return;
			doUpdateItem(item, element);
		}
		public void handleException(Throwable e) {
			super.handleException(e);
			
			
			exception = true;