Possibly it's a stupid question, but i would like to know, why we should mess around with UI Table components or SimpleSelections? It could be much nicer to receive the collection of selected elements into the selection-callback of my controller. Also we could preselect some table rows by filling this collection with the correct POJOs from my model and not with some unknown rowKeys.
PS. The current way of receiving the selection, in my opinion, breakes the MVC pattern quite heavely.