Leger lines
Leger lines are small extra horizontal lines that help show the position of notes that are written outside the five staff lines.
If you encounter an excess of leger lines it might be wise to introduce a clef change or ottava (8va/8ma).
Width (length) and weight (boldness) of leger lines can be adjusted in the Template:Menu dialog.
During edit, you wil see dotted leger lines when hovering the mouse on locations where leger lines are needed:
