Delphi 12 Class TTMSFMXGridCell not found

We are transforming our application from TMS FMX to TMS FNC. We have removed all the FMX components and replaced them with FNC componants. But we het the following message when we open the form: 'Class TTMSFMXGridCell net Found.'
We can't find any reference to the TTMSFMXGridCell.
How can we solve this?