Hi Xedem,

     Yes, the height issue has been replicated and has been forwarded to our developer team. I will inform you as soon as possible if the issue is fixed. 

      On the other hand, to display the previewRow content as multiline, we will need a WebGrid1_LoadPreviewRow server side event and set the DefaultExpanded="false" and LoadOnDemand="true". So that the event will be triggered. Here are the snippet that you can use to set a multiline preview row.

 protected void WebGrid1_LoadPreviewRow(object sender, ISNet.WebUI.WebGrid.RowEventArgs e)
    {
        e.Row.PreviewRowValue = e.Row.Cells.GetNamedItem("ProductName").Text + "<br/>" + e.Row.        Cells.GetNamedItem("ProductID").Text;      
    }

     I hope it helps and please, do not hesitate to ask if you have any other questions. Thank you,

Best Regards,

Andi Santoso