asp.net c# button click refreshing whole page

I placed my repeater inside an update panel like this. Not sure why it refreshes the whole page when i click on these 2 buttons. Not sure why it does not work for these 2 buttons, it works for other buttons though, could it be because i added a new textbox on click of edit and the whole page refresh? As for the delete button, could it be because it couldn't find the position since its deleted? How do I solve this? Please help.

Home.aspx

    <asp:ScriptManager runat="server" />
            <asp:UpdatePanel runat="server" UpdateMode="Conditional">
                <ContentTemplate>
                   <asp:Repeater runat="server" ID="reptater">
                        <ItemTemplate>
                           <div>
                              <asp:LinkButton ID="editThreadBtn" CssClass="editThreadBtn" class="btn btn-default btn-sm" runat="server" OnClick="editThreadBtn_Click" Font-Size="Medium"><i class="glyphicon glyphicon-edit"></i></asp:LinkButton>
                              <asp:LinkButton ID="deleteThreadBtn" CssClass="deleteThreadBtn" class="btn btn-default btn-sm" runat="server" OnClick="deleteThreadBtn_Click" Font-Size="Medium"><i class="glyphicon glyphicon-trash"></i></asp:LinkButton>
                          </div>

                          <%-- show this textbox & button only if user click on edit thread --%>
                          <asp:Panel ID="editTread_pnl" class="input-group" runat="server" Visible="false">
                              <textarea id="editThreadTA" class="form-control" runat="server" style="font-size: 14px;"><%#Eval("Thread_Description") %></textarea>
                                                &nbsp;&nbsp;
                              <asp:Button ID="updateThreadBtn" runat="server" class="btn-info" Text="Update" OnClick="updateThreadBtn_Click" />
                         </asp:Panel> 
                      </ItemTemplate>

                  </asp:Repeater>
              </ContentTemplate>
          </asp:UpdatePanel>
                  

Home.aspx.cs

protected void editThreadBtn_Click(object sender, EventArgs e)
    {
        LinkButton editThreadBtn_ = (sender as LinkButton);

        // get repeater item reference
        RepeaterItem item22 = editThreadBtn_.NamingContainer as RepeaterItem;

        // get the repeater item index
        int index = item22.ItemIndex;

        // find the threadID label control
        Label threadID_lbl = (Label)item22.FindControl("threadID_get");
        int threadID_val = Convert.ToInt32(threadID_lbl.Text);

        foreach (RepeaterItem i in reptater.Items)
        {
            Label Thread_IDs = (Label)i.FindControl("threadID_get");
            int threadID_vals = Convert.ToInt32(Thread_IDs.Text);

            if (threadID_val == threadID_vals)
            {
                Panel thread_editPanel = (Panel)i.FindControl("editTread_pnl");
                thread_editPanel.Visible = true;
            }
            else
            {
                Panel thread_editPanel = (Panel)i.FindControl("editTread_pnl");
                thread_editPanel.Visible = false;
            }
        }

    }


protected void deleteThreadBtn_Click(object sender, EventArgs e)
    {
        LinkButton deleteThread_btn = (sender as LinkButton);

        // get repeater item reference
        RepeaterItem item25 = deleteThread_btn.NamingContainer as RepeaterItem;

        // get the repeater item index
        int index = item25.ItemIndex;

        // find the threadID label control
        Label threadID_lbl = (Label)item25.FindControl("threadID_get");
        int threadID_val = Convert.ToInt32(threadID_lbl.Text);

        SqlConnection con5 = new SqlConnection(constr);
        con5.Open();

        SqlCommand cmd5 = new SqlCommand("UPDATE Thread SET Delete_Status = 'Yes' where ThreadID = '" + threadID_val + "'", con5);
        cmd5.ExecuteNonQuery();

        con5.Close();

        //Response.Redirect(Request.Url.AbsoluteUri);
        showWholeRepeater();
    }