D 365 FO OnActivated(xFormRun eventhandler) extension method to hide the control.

 [FormEventHandler(formStr([FormName]), FormEventType::Activated)]

    public static void LWSOrderTable_OnActivated(xFormRun sender, FormEventArgs e)

    {

        FormDataSource          [DataSourceName]_ds    = sender.dataSource(formDataSourceStr([FormName], [DatasourceTableName]));

        FormTabControl          [ControlTabName]   = sender.design().controlName(formControlStr([FormName], [FormControlName]));

        if([Condition] == NoYes::Yes)

        {

            [ControlTabName].visible(true);

        }

        else

        {

            [ControlTabName].visible(false);

        }

    }