Using “:” in the text filter field seems to have nonsensical results in general. I can apply a #foo:bar tag, and it appears in # tag autocomplete boxes. When I type “:” in the filter box (no other filters active) I see the #foo:bar item…but also a LOT of other items, most lacking “:” entirely. Some nodes in my Outlie even auto-expand to display these items, which should not match.
To be clear though: filtering on just “:” should return the #foo:bar tags, but should also return any items with text that contains a colon. If you added the is:tag filter, you’d get items that have #tags – and also contain “:” . But that would still show items that contain “:” and also-have-any-tag. To truly find just “:” tags, we’d need a wildcard search.
To get around that, some of us put important symbols or differentiators as the first character in tags. I personally use #_, #$, and #@.
