Trill as legato in key editor

I’m going through some old expression maps for EW Symphonic Orchestra to set up a traveling rig and just noticed that the key editor shows legato for trills. I have trill-ht and trill-wt defined and the expression map assigned correctly:

I’m a bit baffled by this one.

Dorico automatically adds the legato playback technique during trills.

ok, but I have trill-ht and trill-wt defined in my expression map. Shouldn’t that be the Base switch used?

Also, in case it wasn’t clear: My sampled trills aren’t triggered by the assigned key-swtich.

Make sure that your playback options are set such that Dorico is set to play sampled trills when available.

Just to close this thread with a solution: yes, default is to never play sampled trills (another default I don’t quite understand) …