The SimpleRow holds its content items within a GridLayout that aligns the default items correctly.
As anchoring is only allowed between siblings or to the parent it is not possible to add additional items to SimpleRow and anchor them to the text/image within the layout.
Also, while it is possible to add custom Items, the SimpleRow is not meant for being extended that much. It is really only a simple row that allows to show text, description and an image or icon. If you require a more customized item, please consider to create a completely new Item from scratch exactly the way you want it to be.