Sorry for the delay in sending this.

When there is no data in the grid, a div element with id is equal to [WebGrid Id]_ND will be shown in the root table of WebGrid. This div element has 100% width.

Is there a way to force the horizontal scrollbar to show at all times?

You might want to try my approach by setting the width of the above div element to be equal to the offset width of WebGrid column header.

Following JavaScript snippet code shows how.

function WebGrid1_OnAfterResponseProcess(controlId, action) {
    var grid = ISGetObject(controlId);
    var colHeaderTableElm = grid.RootTable.GetElement(WG40.COLHEADER, WG40.HTMLTABLE);
            
    if (grid.RootTable.Rows == null)
        document.getElementById(controlId + "_ND").style.width = colHeaderTableElm.offsetWidth + "px";

    return true;
}

I'm using OnAfterResponseProcess client-side event of WebGrid. This event is invoked after the response of a request has been received. The if clause checks if grid.RootTable.Rows is null, then set the width of the div element.

Hope this helps.