Having just purchased a touch screen specifically to support my composing with Dorico 5 Pro, I’m astonished to now discover Dorico 3.5 through Dorico 5.x don’t support touch screens due to some sort of archaic UI library issue. PLEASE rectify this in the next release of Dorico.
Welcome to the Forum.
The archaic library is one of the most used and current UI frameworks, named QT. You will find that in lots of applications crossing borders between Mac, Windows and Linux.
That depends on what QT will provide.