LinkButton inside UpdatePanel not executing onClick javascript

Hello.
So, I have a MasterPage, in which I have an ImageButton and an UpdatePanel. Inside the UpdatePanel I have a LinkButton.
<asp:ImageButton ID="imgPdf" runat="server" ImageUrl="~/Images/pdf.png" OnClick="LnkRelease1_Click" ToolTip="Document1.pdf" Width="31px" /> <asp:UpdatePanel ID="UpdatePanel9" runat="server">
<ContentTemplate>

<asp:LinkButton ID="LnkRelease1" runat="server" OnClick="LnkRelease1_Click" ToolTip="Document1.pdf" Font-Underline="false">View Pdf</asp:LinkButton>

</ContentTemplate>

</asp:UpdatePanel>

As you can see, both components are asociated to the same OnClick event, which should open said PDF documen ...