On my development machine, 64-bit Win 10, with Delphi 10.3.2 Rio and IW 5.1.9, I experience a strange behavior, I can only interpret as an error, and it is easy to reproduce:
Create a new IntraWeb form.
Drop a TIWAdvWebGrid on it, select Columns and delete the 3 columns auto created with the grid.
Right click the grid and select View as Text.
Right click again and select View as Form.
You now see the grid again, and the 3 deleted columns are back !!!!
It happens with a saved unit as well, once it has been closed and are reopened, and when you close your project and reopen it.
In general, whenever the grid is redrawn on the form.
Why is that and is there something I can do about it ?