In Finale you can edit most of the symbols for playing techniques, but in Notion that is not possible. Luckily they play back correctly, but sometimes with the wrong indication. E.g. a violin can play a glissando or portamento, but a piano or accordion can't. Instead they play chromatic runs or glides. However, for the modern accordion, some sort of gliss. effect is often asked in scores (the player glides over a cluster of keys on his keyboard with a flat hand), but sometimes he is asked to play a chromatic run instead. In Notion there is no possibility to make the distinction, since the articulation symbol can't be edited and there's only 'gliss.' or 'port.'.
I assume that that feature could be useful for a number of other playing techniques as well!