Toggle Guide Line Display
Turn the Score Editor guide lines on and off. I have observed the change of settings in the View menu of the Score Editor. Changes between ‘All Objects’ and ‘Selected Objects’.
Note: You can also use the Toggle Guide Lines Display key command, which toggles between All Objects and the last selected display mode.
I do not see any “lines” when the setting is on. What I see is the little box that contains information like position, velocity, and sundry.
You can show an object’s exact time position by displaying guide lines in the Score Editor. Guide lines show exactly the relation of symbols, staves, and time positions).