Setting up a button to trigger both modalPopupExtender and his Click Method

I have this modalPopupExtender, I want it to show a CheckBoxList with some data. I have set up a button to call both the method to fill the CheckBoxes and trigger the modalPopup (TargetControlID). they're all inside an UpdatePanel. with the right triggers. The problem is that when I click the button it shows the modalPopup but doesn't load the method to fill my CheckBoxes...

Also, a linkButton inside the poup (linkButtonCheckAll) just closes the popup when clicked.

When I remove the modalPopup the code works just fine and the list is loaded dinamically with the UpdatePanel.

<asp:UpdatePanel ID="uppLote" runat="server">
        <ContentTemplate>
            <ajaxToolkit:ModalPopupExtender ID="modalLote" runat="server" BehaviorID="popup"
                TargetControlID="buttonViewLote" PopupControlID="panelLote" />
            <asp:Panel ID="panelLote" runat="server" Css开发者_高级运维Class="modalpopup">
                     <asp:LinkButton ID="linkButtonCheckAll" runat="server"

                            Text="Check All Items" onclick="linkButtonCheckAll_Click"></asp:LinkButton>
                     <asp:CheckBoxList ID="checkListLote" runat="server">
                     </asp:CheckBoxList>
            </asp:Panel>
        </ContentTemplate>
        <Triggers>
            <asp:AsyncPostBackTrigger ControlID="linkButtonViewLote" EventName="Click" />
            <asp:AsyncPostBackTrigger ControlID="linkButtonCheckAll" EventName="Click" />
        </Triggers>
</asp:UpdatePanel>

If I completely remove the modalPopupExtender, the code works fine, showing me the list I want with the method "linkButonViewLote_Click" (so, the problem is occurring due to the button triggering the modalPopupExtender is the same that I'm using to get my data, right? Any solutions?

You can try setting the TargetControlID to a dummy control on the page and have buttonViewLote click event call modalLote.Show().