User Agent: Mozilla/5.0 (X11; Linux x86_64; rv:71.0) Gecko/20100101 Firefox/71.0

Steps to reproduce:

1. Press on the "Add Bookmark" star.
2. Press either the selected folder and select "Choose" or simply press the arrow next to the selected folder.
3. Press on "New folder" (it matters not where you are in the hierarchy).
4. Start typing.
5. Double click the "New folder" folder to rename it.
6. Start typing.

Actual results:

When attempting to name the folder, it did nothing for a few moments, and then got saved as "New folder".
When attempting to rename the folder, it worked, however it took forever to register the keyboard input.

Expected results:

The folder should not be saved unless enter was pressed, or a mouse click is registered outside of the text box.

Bugbug thinks this bug should belong to this component, but please revert this change in case of error.

Moriel5 are you using Firefox Sync?

We think this might be triggered by Sync - Marco and I can't reproduce without Sync enabled, but I can reproduce it with Sync.

This seems to be similar to bug 697649, but happens after a few seconds.

Yeah, I am using Firefox Sync, however I am using the built-in Sync, unlike in that bug report, and I've been doing so for several years.

Additional info, now that I have tested this properly:
Not only does creating a new folder take forever, there are (very) noticeable lags when attempting to do anything in the "Add Bookmark" pane, whether it be renaming any item 9not just folders), opening or closing folders, selecting an item, or even just scrolling.

Edit: (not just folders).
My laptop's (Lenovo IdeaPad 300-15ISK) keyboard is breaking apart, from standard usage (not the only issue, and from what I have heard from relatives and friends, reproducible on several different Lenovo IdeaPads from the past few years (including the IdeaPad 310-15, 330-15, and 100-15).

The priority flag is not set for this bug.
:markh, could you have a look please?

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I spent way too long trying to narrow down where this might be happening from, but couldn't find anything conclusive :(

Confirming this based on dupes and the fact I can reproduce it.

Moving back to Sync. The cause of this has been diagnosed as only when Sync is enabled. It might be a combination of Sync & Bookmarks, but we're tracking it in Sync because of the fact it only happens when Sync is enabled.

When a fix for this will come out? This was an old bug that has been re-introduced in a new FF version. Sadly, in 72.0.2 has not been fixed yet. In 71.x there was no problem even with sync enabled!

The severity field for this bug is relatively low, S3. However, the bug has 5 duplicates.
:skhamis, could you consider increasing the bug severity?

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