Paul thanks for your reply. What I conclude from this discussion is that a single clic for playback from the last started position is not in the default customization of Dorico, but you provide means for making your own customization by binding key shortcuts to toolbar buttons. Please tell me if I correctly understood. This could be a compromise although I would have prefered to have this directly hardwired into the product.
Regarding the second part of my question about Human Factor, your answer clearly highlights that you have no HF expert involved in the design. There is a big difference between having developpers “keenly aware of modern UI design principles” and having a proactive approach of HF in your design process. What is performed by the HF expert ? He puts in front of Dorico a representative sample of real users and asks them to realize some tasks. In the background, there are a data logger, eyes tracking and analyzer tools running. HF expert looks at the user’s eyes path on the screen and measures distance, time, clics, keystrokes and a lot of other information that characterize the user’s workload. Then the essence of his job is to OPTIMIZE all this in order to minimize the user’s workload. And this really makes the difference.
A HF approach is very useful when you design a new product from scratch (as you did with Dorico) because it is at this time that you make design choices to be centered on the user. After, it is too late (e.g. look at Finale). Now, according to what was described hereabove, ask yourself in which category you put Dorico: user-centric, product owner-centric or developper-centric?