https://testpilot.firefox.com/experiments/side-view
Step 2:
After installation, users will see the Side View interface appear in the left corner and the double pane window icon on the right toolbar.
Step 3:
To open a web page as a tab, click the Side View icon when you are opening the first web page. We will then see the option to turn on the website in a different window than the desktop or mobile interface. Select another website that is on to switch back to the same window.
Or you can right-click on the active web page and select Open in sidebar to quickly open the website in the second window.
As a result, we will see two websites that are browsed on the same browser but in two other windows. You can browse the web on these two windows at the same time.
Step 4:
At the Side View interface , the browser provides options to close the Sidebar or toggle the Sidebar window to the right. Click the Side View button to display the list.
Step 5:
You can also adjust the window size by adjusting the 2-arrow arrow, then zooming in or zooming in as you like.
Side View utility on Firefox will help you browse 2 tabs on the same interface, without having to switch between 2 tabs to work. We can resize 2 windows to view content more conveniently.
See more:
I wish you all success!