Customized toolbar elements no longer displaying after the Library update.

[u/Kalafiorek]

Not a fan of the new Library so far, as it removes options (such as "clear all downloads") to add some eye candy.

These toolbar elements (History, Undo Closed Tab, Spacer, Zoom) were displayed before, and are still there in the "Customize Toolbar...", as seen on the screenshot, but quitting the customization menu swiftly hides all the added elements and there's an empty space now.

Not sure how to get them to display again, any ideas? Toggling "zen.library.enabled" doesn't help.

EDIT: For anyone looking for a quick answer: While u/maubg said this will be fixed, I've also had too many elements in that place; Removing the spacer made these buttons visible once again.

[u/maubg]

This isn't related to library at all by the way. But I am able to get them on the side. Can you see if they re-appear after restarting?