This add-on did the trick for me appart the wobbly formatting and mostly the lack of a short-key to open in the splitted pane (for example to see the lyrics of a song from a search engine). As I was frustrated about the width's limitation I searched on the issue area of the project homepage and I found the issue #420 which gives a workaround to resize.

Causes some websites to show in mobile version.

Add-on bug with Pinterest desktop keeps forcing itself into mobile view

Hope this gets continuous support.

It works but lacks features that make it worth using. The sidebar is too small for Youtube videos to be watched comfortably, and can only be resized to take up no more than 25% of the space. I don't know why I can't just have two tabs of equal size at the same time. Adblocker also doesn't work, so the tiny tab you have open is a cesspool of ads that make it almost unusable.

works well for discord, followed a guide to expand the size of the sidebar but I would really like a shortcut to open this and a way to set it to automatically open a specific page on launch/when i first open it. Better than the discord-in-sidebar plugin because it uses the mobile view though, so it can be much smaller in the window and still usable

With this addon, some sites automatically switch to mobile lightout.

Firstly, big thanks to the creator for this addon.

Secondly, I have to admit I don't use it in the intended way but rather as a workaround on sites attempting to block adblockers. Specifically Twitch. I don't know how it seems to work, but Twitch will block me from watching streams with an adblocker by giving me an error 90% of the time.

I started using this to circumvent it. For some reason, opening the stream in this side tab will FORCE streams to load in the main tab 100% of the time. Thank you, because without this I'd not be able to watch twitch with adblockers.

A good idea, but doesn't go far enough. Should let me resize the window to whatever size I want. Also, there is no way to get the URL of a page in the sidebar if I've navigated away from the page I started on. Should be an option to pop/open the sidebar back into a normal tab if needed.

Для увеличения боковой панели
1. откройте about: config в Firefox и установите для параметра toolkit.legacyUserProfileCustomizations.stylesheets значение true
2. Меню Firefox -> Справка -> Информация для решения проблем -> Папка профиля -> Открыть папку, создаём папку Chrome
3. В папке Chrome создаём текстовый документ и вставляем в него текст
#sidebar-box {
max-width: none !important;
min-width: 0px !important;
}
Сохраняем и переименовываем в userChrome.css
4. Перезагружаем браузер и радуемся неограниченной регулировкой размера боковой панели.

Seems useful, but having the view limited to 10% of my screen width is just not useful in a lot of cases :(

Works inside the sidebar, I can't use it with Tree Style Tab simultaneously.

Great addon, but it would be awesome if the size of a sidebar could be increased. Currently, it’s too small.

Features I would like to see soon:

1. Add navigation, sorted by importancy:
1.1. Back button - Either own back button in Side View or somehow switch focus from main window to Side View. Working backspace and 3rd mouse key would be idel, after sidebar got focus.
1.2. Possibility to write a web-site address

2. Drag&Drop a bookmark from bookmark bar to Side View

3. Open page from Side View in main window.

4. Make Side View resizable. Now it's only 28% of full screen width. I guess this could be done by UserChrome.css but for some reason it's not loading in my Firefox.

I Love what this does. It is actually a very simple concept - but keeping your calendar or a cloud or mail acc handy on your sidebar shortens my workflows extremely.
I wish they would continue working on it, since I have seen that the last update was in 2018 :/