Always Visible Control Extender not displaying in the same horizontal position

The routine: Click Edit, display a secondary save button in an asp:panel, position is set by the Always Visible control.  The control is positioned at 1,169 px.

Click Save and Hide the Save button.  Click, Edit again and the the save button is no longer visible with a position at 1244px.  The page is never resized and nothing is changed on the page, and the same code is called both times.

 <asp:AlwaysVisibleControlExtender ID="AlwaysVisibleControlExtender1" runat="server" VerticalSide="Top" BehaviorID="AlwaysVisibleControlExtender"
        HorizontalSide="Right" TargetControlID="Panel1" HorizontalOffset="230" VerticalOffset="200" Enabled="True" />
    <asp:Panel ID="Panel1" runat="server" Width="75px" Height="42px" BorderWidth="0" HorizontalAlign="Center" Style="display: block; position: inherit">
        <asp:ImageButton ID="SaveDontEndEditImageButton" runat="server" ImageUrl="~/Images/ButtonImages/SaveEdge.png"
            OnClick="SaveDontEndEdit" />
    </asp:Panel>