Description

The spacer block can only be expanded horizontally in navigation block submenus. It seems like it should instead work vertically—the same orientation as a submenu.

Step-by-step reproduction instructions

1. Add a navigation block (horizontal)
2. Add a link and create a submenu with some more links
3. Try adding a spacer to a submenu

Expected behaviour

The spacer can be used to space out links in the submenus

Actual behaviour

The spacer can only be used to make the submenu wider

Screenshots or screen recording (optional)