Since a series of tied notes is a single event in Dorico, adding a staccato to the tie chain and placing it on the last note of the chain causes the playback to treat the tied notes as though the staccato occurs on the first note. For example, in 2/4 time if you have three half notes tied together, which are tied to a terminating eighth note with a staccato dot over the eighth note, Dorico will play the first half note for half of its normal duration (per staccato playback options) and then silence for the remainder of the tie chain. (In Play Mode, you can see that the Staccato playing technique happens at the beginning of the tie chain, regardless of the actual placement of the staccato dot in Write Mode.)
To work around this, I created a playing technique consisting of just a staccato dot glyph, which is easy to place on the last note of the chain prior to tying them all together. This solves the playback problem, but you have to fiddle a little with the placement of the dot in Engrave Mode to get it aligned correctly.
As a possible future enhancement, it would be nice to be able to put the staccato dot on the last note of the tie chain as we’re able to do today, but provide a way to prevent the playback from stopping halfway through the first note of the chain.
The first thing I tried was extending the Play/Sound bar in the Play piano roll, and discovered it had no effect. I think that’s because the staccato playing technique occurs at the very beginning of the tie chain, so extending the bar doesn’t help as the sound has already been cut off by the PT.
Dorico needs some more development in this area. Firstly, when you have a sampled staccato, as you do for e.g. strings in HSO, then Dorico should be able to determine whether or not the notated duration requires the use of the sampled staccato, or instead some custom length modification. At the moment, playback doesn’t know anything about the way a note is notated, e.g. it doesn’t know that it might be notated as a half tied to an eighth, with the staccato only on the final eighth: it just sees a note five eighths long with a staccato, and so it triggers the staccato technique at the start of the note.
We certainly plan to do more work on this in future, but there’s nothing you can do about this aspect of the interpretation of the score for the time being.