showHeaderMenu

Method which allows you to display the header context menu explicitly for a given column. The default position of the header context menu when invoking this method is the upper left corner of the corresponding column header cell.

showHeaderMenu(event, offsetLeft, offsetTop)
event	The default browser event.
offsetLeft(optional)	The offset to the left from the default header context menu column position.
offsetTop(optional)	The offset to the right from the default header context menu column position.

Example:

<telerik:RadCodeBlock ID="RadCodeBlock1" runat="server">
<script type="text/javascript">
    function ShowFirstColumnHeaderMenu(ev) {
        var grid = $find("<%=RadGrid1.ClientID %>");
        //show the header context menu for the second column in the master table with 10 left/10 top offset
        grid.get_masterTableView().get_columns()[1].showHeaderMenu(ev, 10, 10);
    }
 </script>
</telerik:RadCodeBlock>

<telerik:RadGrid RenderMode="Lightweight" id="RadGrid1" runat="server">
    <MasterTableView EnableHeaderContextMenu="true">
    </MasterTableView>
</telerik:RadGrid> 
<input id="Button1" type="button" value="show header menu" onclick="ShowFirstColumnHeaderMenu(event);" />