How to make side panel resizable:
Updated instructions for Feb 2024 (I'm on Firefox version 123)

- Go to about:support
- in Application Basics section find row called Profile Directory, click on Open Directory button
- Close all firefox running instances
- In that folder, find xulstore.json and open it with a text editor
- Find where it says "sidebar-box":{
- inside those brackets look for "style":
- inside this find width: and replace with the following:
width: 50%; max-width: none !important; min-width: 0px !important;

- if you did it correctly it should look like this: "style":"-moz-box-ordinal-group: 3; order: 1; width: 50%; max-width: none !important; min-width: 0px !important;","checked":"true"

- save the file and close, open Firefox and enjoy!

Cette extension pour firefox est vraiment très utile.
Je ne peut m'en passer. Le seul inconvénient c'est qu'elle n'est pas implémenter de base et qu'elle ne figure pas parmi les extension recommandée par Mozilla Firefox.

merci à la fondation pour le travail que vous faite en apparence.

Uma função boa mas parece que foi abandonada pela Mozilla! Última atualização a cinco anos! Seria bom uma atualização que redirecionasse a barra lateral automaticamente para um tamanho compatível com a leitura! Outra atualização seria ao clicar sobre o ícone do Side View, ele fechasse automaticamente, retornando para a função anterior na barra.

Looks bad in dark mode. The icon of the extension is black on dark background. Also would be cool if the list of recent and current tabs changed to a dark theme when dark mode is enabled. Please remove the icon in the website context menu. Context menus had icons in earlier versions of Firefox but all of the icons got removed.

I hope to see Side View fully implemented natively in Firefox soon.

But it isn't useful as is, with the limited width. I had to fix this with this guide:
https://superuser.com/questions/1276800/customize-the-maximum-width-of-the-firefox-sidebar

Required a change in about:config for me:
(toolkit.legacyUserProfileCustomizations.stylesheets = true)

this what im looking for ! its link split screen in microsoft edge i love this extention!

This is a great idea but it needs some fixing because it seems to have problems and it needs to be available in (Firefox) natively just like it's available in (Microsoft Edge) and needs to function the same way exactly putting it in the sidebar is actually not how it's supposed to function.

Unfortunately there is issue with YTMusic UI when this plugin is activated. Some controls on the player panel not visible when this plugin is active

Best for work. I can use two tab together.

It's very sad this plugin was abandoned 5 years ago, it had a lot of potential. Specially nowadays as other browsers like Vivaldi and Arc come with very powerful multitasking tools.

If at some point, Firefox decides to give support to this plugin again, two suggestions I think would help a lot:
1. Be able to open the side view with a hotkey
2. Be able to navigate (through URLs) in the side view, instead of being stuck in the page you opened it

Can someone maintain this plugin?
Some important features are missing:
* Ability to add multiple website icons in link or right panel.
* Click on any icon to open its website in the panel.

They are useful for workflow!

They would be like Vivaldi side panel