The Caret disappears from the editor when I set the DefaultRowHeight <= 16 and FontSize 8. Should this be the case, or would you expect to see part of the caret whilst editing text within rows of a small height??
It is a known Windows OS edit control limitation that when the height of the edit control is too low for the font used, it will hide the caret. You’ll see the same problem with a regular VCL TEdit control. Either increase the grid row height or decrease the grid font size.