I have StringGrid having buttons in table for some actions…
There is my way to show buttons in grid:
first is to fill table with cell values…
secound is to assign cell with button

var b:TspeedButton;
r:Trect;
begin
r:= StringGrid1.CellRect(1,1);
b:=TSpeedButton.Create(StringGrid1);
b.Parent:=StringGrid1;
b.Top:=r.Top;
b.Left:=r.Left;
b.Height:=r.Bottom-r.Top;
b.Width:=r.right-r.right;
b.Visible:=true;
b.Caption:=’Test’;
b.OnClick:=SpeedButtonClick;
StringGrid1.Objects[col,i]:=b;
StringGrid1.InvalidateCell(1,1);
end;