I clicked on the keyboard icon, and now I can’ find my way back to accessing all the dynamics and tempi etc.
Click the ‘palette’ icon just above it. This is new in Dorico 4, to match Dorico for iPad:
The keyboard icon displays buttons for the various popovers.
The palette icon is for the panels we’re used to on the right (not as many).
aha. I see. In case anyone else reads this, click palette then the related thing you want (dynamics or whatever). Thank you