When you’re in “print” mode, the layout displayed is selected on the left sidebar, but above the image of the page you still see the name of the layout you were just editing in engrave mode. Though minor, this visual contradiction has led me to waste quite a bit of time wondering why the print view of my layout “piano/vocal” layout did not match what I was looking at in engrave mode (because it was actually showing me the full score view).
–Neil
It’s a known issue.
This is not a “known issue” so much as just how the program is designed. The layout selector in the toolbar is disabled in Print mode because it doesn’t apply in that mode. Instead, the layotu selected in the Layouts panel on the left-hand side of the window determines which layout appears in the preview area.
So, a simple question would be: why is that selector still shown, when it’s disabled?
In general controls are not hidden when they are disabled, and familiar controls suddenly becoming hidden can create disorientation and confusion on its own. The fact that you cannot interact with it should give you a strong clue.
Perhaps you could superimpose
over the inoperative pull-down–
just to keep Tantacrul from dissolving in confusion. 
I assume that’s not a serious suggestion!
No, it is not a serious suggestion.
I take the team’s decisions much along the lines I learned growing up in a church school environment:
"God answers all prayers, but sometimes the answer is “no.”
Very appreciative for all you do to make this software (and this forum) as splendid as it is.
OK I get it, but sometimes controls without a function can be hidden to free the space …
and especially when I proofread before printing in need every Millimeter to show a bigger preview.
There is nothing preventing you from using the arrow on the top panel or Cmd/Ctrl-6 to toggle off the top panel in Print mode.