I was also just looking in vain for how to center a frame and was very disappointed to find out that it’s somehow not possible, save for the cumbersome workaround of fiddling with the values manually.
If the Dorico designers are listening, I hope they’ll reconsider the user workflow from the perspective of new users. Screen sharing or screen recording are valuable tools for gaining insight into how users actually use software. Even if this has been done, it would surely be helpful to do it again with new or even moderately experienced Dorico users. I’d volunteer for the developers to look over my shoulder while I try to accomplish fairly basic tasks that are often simple and intuitive in other notation software.
I have great respect for the Dorico team and all the power of this software, though honestly it seems most attention has been given to more complicated workflows while the simplest ones seem to have fallen by the wayside. If Dorico is indeed inspired by desktop publishing software, then how is it even possible that a basic center button has yet to be included even after years of development? (By this I mean centering frame, not centering text within a frame.) It’s understandable that certain features are very complicated and require much thought and development time, but with all respect, I don’t think they should come at the expense of the simplest ones that are easiest to implement. Hopefully this minor request can be implemented in the next update.