I am very sorry, however I do not have any update for the issue. The issue is still active and I still do not have any fixed date for the hotfix release.

Unfortunately, We do not have Windows 2008 R2 in our environment. However, we will try to installed the OS in our environment with the specification you desribed to further investigate the issue. It will take a few days to a week in order to prepare the system in our environment. We will inform you if there is any update.

Since we already using browser native API, we could not boost the performance anymore in the client side. However, you could try aborting the column moving in the client side and move the process to the server side. From your remark, it seems the server process will be quicker for you.

The workaround would be to abort the column moving in client side by returning false in the ColumnMove client side event handler and send the modified column position to the server. After ward we need to call WebGrid RefreshAll function in order to rebuild the column structure in the server during prepare data binding. You could save the column structure in a session on the server side.

Here is the snippet:

//Abort column move and invoke RefreshAll
function wgTest_OnColumnMove(controlId, tblName, oldPost, newPost, currCol, destCol)
{
    setTimeout(function ()
    {
        var grid = ISGetObject("wgTest");
                
        grid.AddInput("newColPost", [destCol.Name + "|" + oldPost, currCol.Name + "|" + newPost].join(";"));

        grid.RefreshAll();

    }, 100);

    return false;
}

protected void Page_Init(object sender, EventArgs e)
{
    //Initialize column session
    if (Session["colList"] == null)
    {
        Session.Add("colList", new string[]{
            "ID2", 
            "checkbox",
            "ID",
            "Interest",
            "Price",
            "DateNow",
            "Description",
            "Link",
            "FirstName",
            "LastName",
            "FullName"
        });
    }
}

protected void Page_Load(object sender, EventArgs e)
{
    //Determine if a there is a modified column 
    if (!string.IsNullOrEmpty(Request["newColPost"]))
    {
        string[] cols = Request["newColPost"].Split(new string[] { ";" }, StringSplitOptions.RemoveEmptyEntries);
        foreach (string col in cols)
        {
            string[] colSect = col.Split(new string[] { "|" }, StringSplitOptions.RemoveEmptyEntries);

            string[] colList = (string[])Session["colList"];
            colList[int.Parse(colSect[1]) - 1] = colSect[0];
            Session["colList"] = colList;
        }
    }

}

void wgTest_PrepareDataBinding(object sender, DataSourceEventArgs e)
{
    if (!Page.IsPostBack || wgTest.ActionName == "RefreshAll")
    {
        wgTest.RootTable.Columns.Clear();

        string[] colList = (string[])Session["colList"];
        foreach (string col in colList)
        {
            WebGridColumn gridCol = null;
            switch (col)
            {
                //Build the WebGrid column
            }

            wgTest.RootTable.Columns.Add(gridCol);
        }
    }
}

Based on my discussion with the developer, I believe that the columing moving API which implemented in the WebGrid is using native browser javascript engine. Based on our test, 500 column moving will be a bit slow in IE, however in other browser, such as FireFox or Chrome it is quite fast.