Repro case for #278

gistfile1.html

<xh:html xmlns:xf="http://www.w3.org/2002/xforms"
    xmlns:xh="http://www.w3.org/1999/xhtml"
    xmlns:xxf="http://orbeon.org/oxf/xml/xforms"
    xmlns:ev="http://www.w3.org/2001/xml-events"
    xmlns:xs="http://www.w3.org/2001/XMLSchema">

    <xh:head>
        <xf:model>
            <xf:instance id="instance">
                <instance>
                    <original>Initial</original>
                    <copy/>
                </instance>
            </xf:instance>
        </xf:model>
    </xh:head>
    <xh:body>
        <xf:switch>
            <xf:case id="first">
                <xf:trigger appearance="minimal">
                    <xf:label>Switch</xf:label>
                    <xf:toggle ev:event="DOMActivate" case="second"/>
                </xf:trigger>
                <xf:input ref="original">
                    <xf:setvalue ev:event="xforms-value-changed" ref="../copy" value="../original"/>
                </xf:input>
                (should update copy)
            </xf:case>
            <xf:case id="second">
                <xf:trigger appearance="minimal">
                    <xf:label>Switch</xf:label>
                </xf:trigger>
                <xf:input ref="original"/>
                (should NOT update copy)
            </xf:case>
        </xf:switch>
    </xh:body>
</xh:html>