UserControl causes full postback

[vellor]

Hi!
I have Placeholder within Update panel. On Page_Load i load user contol via this code:

Control ctrl = LoadControl("~/UserControls/ListViewThumbs.ascx");
                            ucThumbs = (ListViewThumbs)ctrl;
                            ucThumbs.ID = "ucThumbs";


                            ucThumbs.SelectedIndexChanged += new UserControlSelectedIndexChanged(listView_SelectedIndexChanging);
                            ucThumbs.ItemDoubleClicked += new UserControlItemDoubleClicked(UserControlDoubleClicked);

                            ucPH.Controls.Clear();
                            ucPH.Controls.Add(ucThumbs);


                            AsyncPostBackTrigger trigger = new AsyncPostBackTrigger();
                            trigger.ControlID = ucThumbs.UniqueID;
                            trigger.EventName = "ItemDoubleClicked";
                            updateMyDocs.Triggers.Add(trigger);

Below aspx code:

<asp:UpdatePanel ID="updateMyDocs" UpdateMode="Always" ChildrenAsTriggers = "true" EnableViewState = "true" runat="server">
<ContentTemplate>
    <asp:PlaceHolder ID="ucPH" runat="server"></asp:PlaceHolder>
</ContentTemplate>

Clicking in usercontrol causes full postback.. How can i prevent it?