In my post Pop!_OS Tiling – Always Float, I describe Window Exceptions and how to implement them manually. The latest release of Pop!_OS Shell, installed with the most recent Pop!_OS 20.04 update, now includes a graphical tool for managing Window Exceptions.
Floating Window Exception is part of Pop!_OS's Tile Windows feature. It allows you to define a set of windows/applications that will float when they are opened, instead of tiling. This is helpful for utility type applications, like a calculator.
Adding an Exception
To add a new exception, ope
n the application you would like to float. Then open the Floating Window Exception tool from the Tiling Menu. Choose the "Select" button, then select the running window.
You have the option of creation an exception all windows related to the application or only the current window.
After adding the exception, you will see it listed under System Exceptions. In the example below, there are two exceptions for Firefox. You could float all Firefox windows with the "Firefox" exception or just float a specific Firefox window, like "Firefox / Employee Home - Mozilla Firefox". When floating a specific window, it's based on the window title. If the window title changes, the exception will not work.
System Exceptions
Out of the box, Float Windows Exceptions include "System Exceptions", which appear to be community curated recommendations. System exceptions default to "On". I don't agree with all of the system exceptions and turned a few off.
config.json
Floating Window Exceptions settings are stored in .config/pop-shell/config.json. Prior to the new graphics tool, I updated this file manually. The file format is easy to understand and update.
I like to sync this file to multiple computers to keep my configuration the same on all machines.