is it possible to remove or hide this unnecessary tone change?
Try moving your instrument change one bar later.
Instrument changes are automated…
For the time being, the best you can do is insert something else in that bar in the original instrument (e.g. a text item containing an empty space), so that Dorico thinks the original instrument is still active, and will thus snap the instrument change forward to the next barline.
That does not work unfortunately. Notes are the only things that matter to delay the change. In fact, anything that is written in the intervening bars of the initial instrument (dynamics, playing techniques etc …) will actually disappear and be replaced by the instrument change. I have not been able to figure out a decent workaround for this. Having a property where you can choose the key change to appear 1. Immediately; 2. At the next intervening key change; 3. On the first measure where the new instrument begins; would be a wonderful addition. But I realise you know this!
You can add a note in an unused voice, scale it to 1% scale factor, and set the ‘Ends voice: immediately’ property, then.
Mille mercis Daniel. It’s OK