Hi @AndreRocha,

Thank you for your report. We've created a task in our backlog to investigate and add this use case. Refer to the code ROU-4320 in future release notes.

As a workaround you can use some custom code to cover this case:

1. Create a new ClientAction with these input parameters:
   • GridId: Text type
   • RowNumbers: Integer List type
   • isSelected: Boolean type
2. Add JSONSerialize and assign to the Data property, the RowNumber input parameter
3. Add a JavaScriptNode with these input parameters:
   • GridId: Text type
   • RowNumbers: Text type
   • isSelected: Boolean type
4. In the JavaScriptNode enter the code:

    let grid = OutSystems.GridAPI.GridManager.GetGridById($parameters.GridId)

    let rowNumberList = JSON.parse($parameters.RowNumbers)

    if (grid.features.rowHeader.hasCheckbox) {

        rowNumberList.forEach((index) => {

            grid.features.selection.getMetadata(index).isChecked = $parameters.isSelected;

        });

        grid.provider.collectionView.refresh();

    } else {

        rowsIndex.forEach((index) => {

            grid.provider.rows[index].isSelected = $parameters.isSelected;

        });

    }

Now you can use this Client Action the same way you would use the SetRowAsSelected.

I've attached an OML file with this fix implemented for better understanding.

Hope it helps,

Giuliana.