This is a steps to reproduce my issue :
1- Create a new project;
2- Drop a TTMSFMX grid on a form and a Button;
3- Set this code in the Button onClick event:
TMSFMXGrid1.options.Mouse.RowDragging := True;
TMSFMXGrid1.Cells[2, 4] := 'This is text .';
4- Run projet, click Button and :
5- Drag the row containing text on a row below.
6- I get "out of range" error message.
Any suggestion ?