I would stay away from using xsi:type.  Instead, I would change schema/xml 
to something like:

<tabs>
    <selected>
        <tab id="General" order="1" />
    </selected>
    <tab id="Edit" order="2" />
    <tab id="View" order="3" />
</tabs>

Alternatively, you can make "selected" attribute optional and have it take 
only one value - true.  Then use a uniqueness constraint to make sure there 
are no duplicates.  This however won't guarantee that there's a selected 
tab.

-- 
Stan Kitsis
Program Manager, XML Technologies
Microsoft Corporation

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"Thomas Malia" <tommalia@w...> wrote in message 
news:OCT1fgWiGHA.3956@T......
> Would a reasonable workaround be to create different types (purhaps all as 
> restrictions of a super type) and make then members of a group?  Then in 
> the XML file explicitly define the type of each element (basically use the 
> type in lue of the attribute)?
> I could be WAY off base here... still learning my self
>
> "Jonathon J. Howey" <JonathonJHowey@d...> wrote in 
> message news:8A934A75-85B9-4A19-AB90-70973AEC4506@m......
>> Blah, I was afraid so, thanks.
>>
>> "Stan Kitsis [MSFT]" wrote:
>>
>>> You cannot do this using Xml Schema.
>>>
>>> -- 
>>> Stan Kitsis
>>> Program Manager, XML Technologies
>>> Microsoft Corporation
>>>
>>> This posting is provided "AS IS" with no warranties, and confers no 
>>> rights.
>>>
>>>
>>> "Jonathon J. Howey" <JonathonJHowey@d...> wrote in
>>> message news:9744A4B7-9A0B-446F-AFF7-7DEE282BC4EA@m......
>>> > Am i able to create a restriction in my XSD for the following case:
>>> >
>>> > <tabs>
>>> > <tab id="General" order="1" selected="true" />
>>> > <tab id="Edit" order="2" selected="false" />
>>> > <tab id="View" order="3" selected="false" />
>>> > </tabs>
>>> >
>>> > So what I would like to do, is to say that only one tab can have
>>> > selected="true".  A unique restriction won't work as it will cause
>>> > problems
>>> > for the false ones
>>> >
>>>
>>>
>>>
>
>