If you want to have a "ReadOnly" kind of control, Enabled is a good choice but the control looks not good, what I do when I need such is a little trick.I am sorry, I just tested it but Lazarus/FPC/LCL works different than the Vcl for Delphi does works.
Add a panel, client align on that panel your grid, enable = false that panel, voila, you have same colored grid but it can not be focused.
Was it that what you wanted to achieve?