Is it possible to duplicate Excel type navigation/edit behaviour. i.e. when you start typing the grid switches into edit mode but when you drag with the mouse it selects cells?

Try to set goEditing = true & goRangeSelect = true in grid.Options as well as grid.MouseActions.RangeSelectAndEdit = true

Thanks for the pointers. After a bit of investigation, all I need to do to mimic Excell behaviour is handle the OnKeyDown() event so that the arrow keys switch the grid out of edit and move to the next cell and the alphanumeric keys switch the grid back into edit mode.
Setting Grid.SelectionRectangle := True and the following code in the OnMouseDown()

 if Grid.SelectedCellsCount >1 then Grid.SelectionColor := $00EACAB6
  else Grid.SelectionColor := clWhite;
gives the Excell behaviour as regards selection.

This seems to me to be a more intuitive and flexible behaviour than pressing ENTER to move to the next cell. Had you thought of including it as an optional property in a future version?

We'll inspect the Excel behavior close and will see if there is anything that can be done to optionally make it mimic Excel better. The solution with setting SelectionColor will fail though as soon as cell coloring is used.