Updatepanel still reloades all page

Hi,

I have a code like this:

<asp:UpdatePanel ID="UpdatePanelMjesto" runat="server">
<ContentTemplate>
<asp:Label ID="lblMjesto" runat="server" Text="MJESTO:" Width="150px" />
<asp:Button ID="btnDodajMjesto" runat="server" Text="Dodaj mjesto" />
<asp:DropDownList ID="ddlMjesto" runat="server" Width="705px"/>
<br />
<asp:Repeater ID="repeaterList" runat="server" EnableViewState="false">
<ItemTemplate>
<div>
<div>
<asp:Label ID="lblName" runat="server" CommandName="lblName" Text='<%# Eval("MJESTO")%>' Width="700px" />
</div>
<div>
<asp:LinkButton ID="linkButtonDelete" runat="server" CommandName="LinkButtonDelete" OnClientClick="return confirm('Are you certain you want to delete this record?');">
<asp:Image ID="ImageDelete" runat="server" ImageUrl="~/slike/ikone/ne.png" Height="25px" />
</asp:LinkButton>
</div>
</div>
</ItemTemplate>
</asp:Repeater>
</ContentTemplate>
</asp:UpdatePanel>

But each time I do anything in updatepanel (prest delete or pres the button inside upate panell whole page reloads.

Any Idea?

Thx