Thread:Extension talk:Semantic Watchlist/No items in watchlist/reply (2)

I think the issue here is how SWL handles namespace/category/concept names. It seems to require an underscore. I notice that your watchlist category name is "Calendar items". What if you change it to "Calendar_items"? I had a similar issue and adding the underscore worked for me.

I have submitted bug report to Bugzilla.