{:When to create the instance (and
    wincontrol) associated with the plugin.
@enum ipImmediate Create the instance immediately when the container is created.
@enum ipDefault Use instancing policy specified by container (or user).
@enum ipLazy Don't create the instance before the user activates the panel associated with the plug-in (ie delay instance-creation to the latest possible point in time).
}
TdlInstancingPolicy = (ipImmediate, ipDefault, ipLazy);