In Script Workspace you can right click on the tab of the active script and get a small pop-up menu. In that menu is an option 'Check for Problems'. I stumbled across this nice little feature back in 16 - I don't know if it was available in 15.
Regardless, in 16 when you selected the 'Check for Problems' option it would go through your current script and highlight lines that had obvious errors, and a small red dash would appear in the scroll bar area at the right, indicating where in the script any errors might be, even if they weren't currently visible. In 17, the small dash in the scroll bar area doesn't appear to be showing up for me. It would be nice to have, so that I don't have to manually scroll through 400+ lines of a script just to look for red-highlighted lines.
OS X 10.13.4
Restarted FMP with the same behavior - no red-dash in scroll bar.