Frame relativeTo another frame only onload?

I have code like that (game is Runes of Magic):

<Frame name="ComeOnInFrame_Config" inherits="UIPanelBackdropFrame" enableMouse="true" parent="UIParent" hidden="true" frameLevel="1">
    <Size><AbsDimension x="650" y="380" /></Size>
    <Anchors><Anchor point="CENTER"/></Anchors>
    <Scripts>
        <OnMouseDown>ComeOnInFrame_Config:StartMoving("CENTER");</OnMouseDown>
        <OnMouseUp>  ComeOnInFrame_Config:StopMovingOrSizing(); </OnMouseUp>
    </Scripts>
</Frame>

<Frame name="ComeOnInFrame_QuickSave" parent="UIParent" inherits="UIPanelBackdropFrame" enableMouse="true" hidden="true" frameLevel="5">
    <Size>
        <AbsDimension x="250" y="250" />
    </Size>
    <Scripts>
        <OnMouseDown>ComeOnInFrame_QuickSave:StartMoving("CENTER");</OnMouseDown>
        <OnMouseUp>  ComeOnInFrame_QuickSave:StopMovingOrSizing(); </OnMouseUp>
    </Scripts>
    <Anchors>
        <Anchor point="TOPLEFT" relativeTo="ComeOnInFrame_Config" relativePoint="BOTTOMRIGHT">
                <Offset><AbsDimension x="-250" /></Offset>
        </Anchor>
    </Anchors>
</Frame>

I added relativeTo ComeOnInFrame_Config, because I want to get ComeOnInFrame_QuickSave when openned, at bottom right of relativeTo. It's because better looks when openned, BUT ComeOnInFrame_QuickSave could be moved to another place of screen as one, seperatelly frame. Problem is when moving ComeOnInFrame_Config, the ComeOnInFrame_QuickSave is also moving (wherever it is).

Is there solution for this (not moving ComeOnInFrame_QuickSave when ComeOnInFrame_Config is in moving) with available widget elements - http://ift.tt/1kXfliQ? Maybe something with OnMouse events?

Counting location by pixels is not possible, because different screen resolutions.

I am newbie in XML and I don't know how it should be correct for no error generating.

Thanks in advance for each answer! Greetings