(CustomizableUI controls toolbar visibility state, too. That's persisted in XUL store, which will need changes to Sync: https://searchfox.org/mozilla-central/rev/b29663c6c9c61b0bf29e8add490cbd6bad293a67/browser/base/content/browser.js#5682)

I would like to have this feature, too. Whenever I install a new device, I have to re-customise the toolbar, which is quite boring. :)

Anyway, it still is an issue on FF 65.0.2 (64-bit) on any OS (just to note).

Would also be keen to see this feature. First thing I do after sync is to move my toolbar around.

6 years. wow.

(In reply to Daniel from comment #20)

6 years. wow.

It's not clear exactly how we should do this, or even if we should do it at all. My customizations tend to be based on the size of the screen the device has, so personally I would consider it broken if syncing "preferences" meant my toolbars were identical across all devices - and I'd be forced to turn off preference syncing, so I'd get no preferences synced at all.

One way could be renaming preferences into "settings", and create a new Sync option "User Interface". Would it then be a problem in your use case?

That would certainly be an improvement. We really need to look at everything which hangs off https://bugzilla.mozilla.org/show_bug.cgi?id=1269548 and see if there is a sane, small number of additional options we could add which could handle most things there, or some other way to capture this "long tail" of things some people would like synced, but which some other people would find strange if they were.

But it could be disabled by default, so other people who find it strange wouldn't notice?

I don't think this alone is enough to justify a new setting without considering all the other things hanging off that bug.

Which "other things" are hanging off this bug? o_O

I was referring to the "syncmore" bug. You continuing to needinfo me isn't going to make this happen any time soon.

With more and more features being removed from their respective prior locations and menus and thus needing toolbar buttons of their own now, the priority of this request should be increased.