Well, the thing is this: No application running in fullscreen mode should ever break the screen’s boundaries, unless explicitly told to do so by some special, native function of that software (or in the rare case a screen with insufficient resolution is used, which cannot display the complete UI even at 100% desktop scaling - speaking of the latter, there is no minimum resolution defined for Dorico in the official system requirements on the Steinberg website). A function like the status bar which isn’t explicitly an overall width control function, should always either crop the information, invoke a scroll bar or refuse to enable more info while in fullscreen mode.
When in window mode (non-fullscreen) however, applications are allowed to break the boundaries to enable easy repositioning by the mouse. This also applies to dialogs opened as windows by their mother application running in fullscreen. (The daughter windows should initially open in such a way that every relevant function is immediately accessible and not off-screen though.)
Interestingly, I could reproduce what @dspreadbury describes as intended behaviour only while in window mode, as I presume it is indeed intended, but when in fullscreen mode, my Dorico never broke the screen’s boundaries, both on my Surface Pro’s inbuilt screen (2880p width scaled at 200%, thus having 1440p effective width) as well as on my 34" ultrawide. In fullscreen mode, an overflow of information on the status bar resulted in pieces of that information being cropped, as I would expect it to, so all is fine on my machines regarding the status bar’s behaviour.
That said, I do not question the issue described by @Barry_Chabala being persistent, as it does seem to occur on his machine even in fullscreen mode, which is certainly not an intended behaviour (at least I cannot imagine it to be). To me this is reminiscent of something that I described some time ago regarding the Project Info dialog, but of course I can’t know if these two phenomena are in any way related within the code.
Barry, can you provide us with your screen’s pixel width and the desktop scaling ratio you are using?