\set Staff.tempoHideNote not working

[Patrick Karl]

Neither of the following attempts at hiding the "quarter note = nnn" works:

{ \set Staff.tempoHideNote = ##t
  \tempo "Allegro" 4=120
  c''4 d'' e'' f''
}

{ \tempo "Allegro" \set Staff.tempoHideNote = ##t
  \tempo 4=120
  c''4 d'' e'' f''
}

I think the first one should clearly work, but it simply does nothing.

So, what's the best way to do this?