Go to last item in TTMSFMXTableView

I searched and found this topic How to scroll manually in FMXTableView? - #9 by Werner_Weiss
It seems to give the right answers for my problem, but they do not work.
I add items manually to a TTMSFMXTableview.
Right after I do a TMSFMXTableview.Lookupitem(TMSFMXTableview.Bottomitem, true, false);
The booleans are tested in every combination..
I tried the other recommendations like Scrollpositions and so on.
Nothing will scroll the tableview a single row.
Then I figured out bottomindex is -1.
Why is that?
Do I have to check some properties or run a method after inserting the items?

Can you try the following functionality

TMSFMXTableView1.PositionItem(TMSFMXTableView1.Items[TMSFMXTableView1.Items.Count - 1]);