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
}
	/**
	 * Non-recursively tries to find the given element as a child of the given parent item.
	 *
	 * @param parent the parent item
	 * @param element the element
	 */
	private Widget internalFindChild(Item parent, Object element) {
		Item[] items = getChildren(parent);
		for (int i = 0; i < items.length; i++) {
			Item item = items[i];
			Object data = item.getData();
			if (data != null && equals(data, element))
				return item;
		}
		return null;
	}
	/**
	 * Recursively tries to find the given element.
	 *
	 * @param parent the parent item
	 * @param element the element
	 */
	private Widget internalFindItem(Item parent, Object element) {
		
		Object data = parent.getData();
		if (data != null) {
			if (equals(data, element))
				return parent;
		}