In ExtensibleFilter, we only execute the filters which match to path of request URI. So we should match to path regardless portal container name.
In sample extension, we had SampleFilter with pattern was /.*. If we change pattern to /simpleFilter, SimpleFilter cannot be executed because the path URI is /portal/simpleFilter (with portal container name is 'portal'). Actually, we want do filter to SimpleFilter when in the path has /simpleFilter regardless portal container name