FileMaker Pro 17, Windows 10.
My clients are seeing an annoying and ugly little cosmetic issue if you place a button bar with icons into a top navigation part and you zoom the view. I couldn't easily find any reference to this earlier, though I think the bug has been around a while.
Fairly easy to reproduce, screen shots below and sample file linked.
Create a new file and set the layout style to minimal (I think it occurs on all styles).
Add a top navigation part and a header part (for comparison).
Add button bars with a few segments, decent labels with any of the standard icons.
Switch to browse mode...all good:
Now zoom to 150%...gah!
The text blocks in each segment reduce in size causing an ugly text wrap.
As you can see, the header part is fine, it is just top navigation.
This happens regardless of how large the button bar is. It's almost like the left/right padding in the segment is scaled along with the zoom %.
Sample file at this temporary location: