I tried to reproduce the reported problem in my local test by viewing IntegrationwithWebCombo.NET.aspx WebGrid sample file in IE 11 browser but my efforts were not successful - the page was accessed without any issues.

I would need you to elaborate on your specific scenario and possibly provide us with a simple sample that replicates the problem (or sent the modified sample of IntegrationwithWebCombo.NET.aspx that reproduce the problem) and step-by-step guide that we can use to observe the problematic behavior.

Seems to happen when webcombos are created programmatically. I forgot to mention that this is the case in our project.

I get the same behavior when running the corresponding sample from Intersoft (WebCombo/Programmatic.aspx). All other samples work ok.

Sorry for any inconvenience this problem may have caused you. This problem has been forwarded to WebCombo development team. It is filed under ASPNET-187.

Should I heard anything regarding ASPNET-187, I will let you know by updating this thread.

Edited on October 19, 2015 3:15 AM
Reason: provide solution.

If you are experiencing this issue when create WebCombo programmatically, set the ResultBoxWindowType of WebCombo's LayoutSettings to Normal should resolve the problem.

I modified Programmatic.aspx sample of WebCombo by adding a line of code in combo_InitializeLayout LayoutEventHandler and find that the reported problem is no longer persist.

protected void combo_InitializeLayout(object sender, LayoutEventArgs e)
{
    // Setup Behavior
    WebCombo combo = (WebCombo)sender;
    combo.DataTextField = "ContactName";
    combo.DataValueField = "CustomerID";
    combo.LayoutSettings.ResultBoxWindowType = DisplayType.Normal;
}

Please let me know if you have different result.

Glad to know that set ResultBoxWindowType to Normal resolve the reported problem.

Should you need further assistance or run into any problems regarding our controls, feel free to post it into our forum. We would be happy to assist you again.