Hierarchical tags: viewing all elements with children tags

Perhaps this has come up before, but I wasn’t able to find it.

Is it possible to click on a tag in the source list and view all items that have that tag as well as all items that have children tags of that tag? I thought I could do this by option-clicking (not sure why I thought this), but it isn’t working.

If this isn’t available, please please please make it available. I don’t really see much use for hierarchical tags if they don’t have some sort of recognition that they have a relationship (even if it’s hidden behind an option-click or similar).

Not currently, but that’s something I’d like to add.