The system track allows you to select all items, including system objects, on all staves in the system across the selected beats.
Prerequisite
The system track is shown.
Procedure
Result
Everything on all staves in the selected beats is selected and highlighted, including system objects, notations, and signposts.
Note
If you then delete your selection, any signposts included are also deleted. This can affect the page layout; for example, by removing ossia staves whose signposts were included in the selection.