Finder Window Sidebar Shrinkage

Four hours ago my sidebars shrank. That is, the Finder Window Sidebars did.

All the shortcuts - about eight of them - down to iCloud, have vanished.

As far as I know I did nothing to cause this. The settings in Finder preferences are the same. No matter what i do with the settings, the shortcuts will not reappear.

This is a bit of a nuisance, and help would be appreciated.

Laurence.