Breaks bookmark manager and SessionSync

[gitvalds]

This is a Bug Report

Description

A clear and concise description of what the bug is.

Cannot copy paste bookmarks folders in "Manage Bookmarks". New sessions in SessionSync are empty.

Steps to reproduce the problem

Copy paste a bookmark folder in "Manage Bookmarks". Alternatively or in addition, create a new session in SessionSync.

Expected behavior

A clear and concise description of what you expected to happen.

Copy-pasted bookmarks folders in "Manage Bookmarks" contains the same bookmarks as the original folder. New sessions in SessionSync contains a bookmark for each open tab.

Specifications

• Version of the add-on:

3.1.0

• Firefox edition: Firefox (regular edition) / Developer Edition / Beta / Nightly / Other (please specify) regular for Linux desktop

• Firefox version: 86 and 87; probably also some older versions;

• Firefox language: English / Other (please specify) english

• Platform/OS: Windows / macOS / Linux / Other (please specify) Fedora

• Platform/OS version: 33

Screenshots

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Additional context

Add any other context about the problem here.

On Firefox 86 and 87, probably also before them, I noticed that when saving a new session in SessionSync, it was empty. Today I uninstalled SessionSync, thinking that it had a bug. I went to Library -> bookmarks -> manage bookmarks and copy pasted the SessionSync folder, to have a backup before installing Tab Session Manager. It copied the folders and all (I think) its sub-folders, but almost all of them were empty. In a couple of folders in 50 folders, there was one bookmark. I repeated the process a few times, also with another small folder with just six bookmarks in it. Always waiting, to be sure I was not interrupting the copy, and always restarting Firefox in between the attempts. I googled for such a bug in Firefox but found nothing. Then it came to me that SessionSync uses bookmarks as sessions. So I uninstalled the only other addon that has to do with bookmarks, which is "Default bookmark folder". I restarted Firefox, and tried again to copy paste the folders of bookmarks and it worked. Then I reinstalled SessionSync and also its problem was gone, meaning that I could save a new session without it being empty.

[gitvalds]

This happens also on another computer, with the same operating system and browser as above.

[gitvalds]

When uninstalling the addon, all the tabs currently open got added to the root directory of the "bookmarks menu", which for me was also the "default bookmarks folder", so I am not sure if they would have been added to a different folder if my default was different.