Option to show anchor points for all lines and symbols
Double-clicking a line allows you to see where it's endpoints are anchored to in the score. This is useful for spotting when a line has been added incorrectly, such as this volta (which should be anchored to the first barline rather than the second).
When checking a score for errors (think OpenScore), it would be useful to be able to display all anchor points for all lines at once (perhaps via an option in the View menu) so that errors could be spotted without having to click on each line individually.
It would also be helpful to display the anchor point for other symbols and text. Perhaps something like this:
This allows the user to see at a glance:
1. Which note or rest the symbol is anchored to.
2. The symbol's default position.
3. How far the symbol has been moved from its default position.