The template which should be instantiated.

Unset by default, meaning all templates will be instantiated (assuming MatchKey, and TemplateKey are also unset).

If you intend on using a binding, or expression, for this value it is recommend to set Defaults as well. This avoids an momentary creation of the defaults while the binding has not yet resolved.

<Instance Match="{type}" Defaults="None">
    <Panel ux:Template="side"/>
    <Panel ux:Template="fore"/>
</Instance>

{type} may resolve to an async JavaScript variable, meaning it won't produce an immediate value. This will result in Match not yet having a value, thus all templates would be instantiated by default. Defaults="None" prevents this behaviour.