MS4.4.2 > Fretboard Diagrams — Fret Mark hot spots
The red rectangles in the attached image show the "hot spot" areas for toggling Fret Marks.
• The rectangle on the right indicates the actual and appropriate area
• The rectangle on the left extends needlessly leftward of the Fret Marks.
I noticed this when clicking the Fret Number so see if that would reveal more properties. To my surprise clicking the Fret Number deselected the Fret Mark to the right of it.