Cannot set default filters on Activity Streams

[karl-os]

Hello

I can filter out sub-forums on the activity streams, so they do not appear in the results:

 

However I cannot do this when I create a new stream in AdminCP:

The only option I have is to include all topics, or none. Am I missing an option somewhere to allow this type of filtering? I'd like to create a default stream that excludes certain sub-forums. Cheers