The Version History says:
To create a vertical line spanning multiple staves, select a note in the voice on the top staff, then use Ctrl+click (Windows) or Command-click (Mac) to select a note in the voice on the bottom staff, then click the desired line type. The line will be created to enclose the chords on the selected staves.
I can’t get this to work. If I select one note on the top staff and one note on the bottom staff, I only get a line spanning the notes on the top staff.