modal popup extender on gridview hovermenu extender

Question

I created a hovermenu extender from ajaxtoolkit on one of the columns on gridview as below.

Columns>

asp:TemplateField>

ItemTemplate>

asp:Panel ID="panel2" runat="server" style="display:none;">
asp:LinkButton ID="lnkEdit" runat="server" CommandName="Edit" Text="View" />

/asp:Panel>

asp:Panel ID="panel1" runat="server"><%# Eval("Number") %> /asp:Panel>
ajx:HoverMenuExtender ID="hme2" runat="Server" PopupControlID="panel2" PopupPosition="Left" TargetControlID="panel1" HoverCssClass="popupHover"
OffsetX="0" OffsetY="0" PopDelay="50" />
/ItemTemplate>

/asp:TemplateField>

Now when I click on the view I want to open a modal popup using the modal popup extender from ajaxtoolkit.

asp:panel id="panel0" runat="server">Some text

ajx:ModalPopupExtender ID="modal" runat="server" TargetControlID="btnShowPopup" PopupControlID="panel0"> /ajx:ModalPopupExtender>

                asp:Button id="btnShowPopup" runat="server" style="display:none" />

but this doesn't open modal popup. I get an error in the browser saying gridview has fired an event RowEditing which wasn't handled

I also have the below in my code behind protected void grid_RowCommand(object sender, EventArgs e) { modal.Show(); }

any help is greatly appreciated