I am using the following grid:
   <telerik:RadGrid style="overflow: hidden" CssClass="dm-Grid" ID="gridView" runat="server" AllowPaging="false" PageSize="25" Skin="TylerSilver" EnableEmbeddedSkins="false" EnableViewState="true"
            ExportSettings-ExportOnlyData="true" ExportSettings-IgnorePaging="true" AutoGenerateColumns="false" SortingSettings-SortedBackColor="#F0F0F0" EnableAlternatingRowColor="true"
            EnableAjaxSkinRendering="true" AllowSorting="true" ShowGroupPanel="false" GroupPanel-Enabled="false"
            ClientIdMode="AutoId" AllowFilteringByColumn="true" onneeddatasource="gridView_NeedDataSource" Onitemcreated="gridView_ItemCreated" onitemdatabound="gridView_ItemDataBound">
            <clientsettings>
        <clientevents onrowselected="RowSelected" onrowdeselected="RowSelected" oncolumnclick="OnColumnClick" OnColumnSwapped="ColumnSwapped" OnGridCreated="OnGridCreated"/>
    </clientsettings>
        </telerik:RadGrid>

Columns are dynamic, created in code-behind to match configurable datasets, via gridView.Columns.Add.  Each column has UniqueName, SortExpression, and HeaderText properties set - first two to the field name, last to plain-English version of the field name with spaces, etc.  Data binding is via a data table created from search results:

 gridView.DataSource = allDocumentsTable;

and using the following JS to activate the header cell context menus:

 function ShowColumnHeaderMenu(ev, index) {
            var grid = $find("<%=gridView.ClientID %>");
            var columns = grid.get_masterTableView().get_columns();
            columns[index - 1].showHeaderMenu(ev, 5, 5);
        }

I'm able to group columns using the menu but the "ungroup" command in the menu does not work.  If I turn on the grouping panel as a test (we do not want this UI style in production code), I can ungroup columns using the panel, but that does not change the behavour of the ungroup command in the header menu; it still does not work.

I've tried this with the Q2 2014 release and the problem is reproducible in that version.

Vertical Column Headers using rgRotateHeader seem to be a different, less readable, font than the regular horizontal column headers.  Please see attachment.  All those column headers are set to the same font.  To my eye, the rotated headers look quite poor.

Add RadGrid Support per column/per grid for timezone like the RadScheduler 
Same with the  RadDateTimePicker, RadDatePicker and Calendar.

RadGrid cannot edit in IE8 under 2014Q2
javascript thows errors:
URI: http://localhost/Telerik.Web.UI.WebResource.axd?_TSM_HiddenField_=RadScriptManager1_TSM&compress=1&_TSM_CombinedScripts_=%3b%3bSystem.Web.Extensions%2c+Version%3d4.0.0.0%2c+Culture%3dneutral%2c+PublicKeyToken%3d31bf3856ad364e35%3azh-CN%3a8f393b2b-3315....

To fix the upper problem, we appyied 2014Q2SP1, however, in IE8, javascript thows new errors:
“sys is undefined” 
and the RadGrid does not display in web. But this is ok in debuging mode.

The title says it all. Right now there's only a check all option.

In the out of the box Grid CheckList filter the only way to clear all items for a checklist filter once filter items have been selected is to:

1) Uncheck each one individually
2) Click "Check All" to check all, then click "Check All" again to uncheck all.

It would be great to just have a clear all/clear selection button in the filter list.

The functionalities listed below are officially not supported with multicolumn headers: 
•Frozen Columns;
•Show/Hide on the client;

Please provide the solution for these known issues in next release

When trying to batch edit cell values of the Grid via e.g., RadEditor (GridHTMLEditorColumn or RadEditor in EditItemTemplate of GridTemplateColumn) the cell value always result to a plain text.