Not sure if this problem is caused by extlib or dojo (I am using 1.6.1)

I created an xpage with a dojo stack container (& child dojo stack panes). When I added a dojo number spinner the browser reports a error in dojo.js (line 81) "this._set is not a function".

The error only occurs if you have both controls on an xpage (if the numberspinner is outside the stack pane it will still display, but not if it inside a stack pane)

example code -

1. Only numberspinner  - works

<?xml version="1.0" encoding="UTF-8"?>
<xp:view xmlns:xp="http://www.ibm.com/xsp/core"; xmlns:xe="http://www.ibm.com/xsp/coreex">;
    <xe:djNumberSpinner id="djns1"/>
</xp:view>

2. Only stack pane  - works

<?xml version="1.0" encoding="UTF-8"?>
<xp:view xmlns:xp="http://www.ibm.com/xsp/core"; xmlns:xe="http://www.ibm.com/xsp/coreex">;
    <xe:djStackContainer id="djsc1">
        <xe:djStackPane id="djsp1"/>
    </xe:djStackContainer>
</xp:view>

3. numberspinner outside stack pane  - works but error message

<?xml version="1.0" encoding="UTF-8"?>
<xp:view xmlns:xp="http://www.ibm.com/xsp/core"; xmlns:xe="http://www.ibm.com/xsp/coreex">;
    <xe:djNumberSpinner id="djns1"/>
    <xe:djStackContainer id="djsc1">
        <xe:djStackPane id="djsp1"/>
    </xe:djStackContainer>
</xp:view>

4. numberspinner inside stack pane  - fails to display number spinner

<?xml version="1.0" encoding="UTF-8"?>
<xp:view xmlns:xp="http://www.ibm.com/xsp/core"; xmlns:xe="http://www.ibm.com/xsp/coreex">;
    <xe:djStackContainer id="djsc1">
        <xe:djStackPane id="djsp1">
            <xe:djNumberSpinner id="djns1"/>        
        </xe:djStackPane>
    </xe:djStackContainer>
</xp:view>