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
}
		if (includeChildren && getExpanded(item)) {
			Item[] children = getItems(item);
			if (children != null && children.length > 0) {
				return children[0];
			}
		}
		
		
		Item parent = getParentItem(item);
		if (parent == null) {
			return null;
		}
		Item[] siblings = getItems(parent);
		if (siblings != null && siblings.length <= 1) {
			return getNextItem(parent, false);
		}
		for (int i = 0; i < siblings.length; i++) {
			if (siblings[i] == item && i < (siblings.length - 1)) {
				return siblings[i + 1];
			}
		}
		return getNextItem(parent, false);
	}
	/**
	 * Returns the parent item of the given item in the tree, or
	 * <code>null</code> if there is parent item.
	 *
	 * @param item the item
	 * @return the parent item, or <code>null</code> if none