Typical situation is that I type something (worst case is my password) in some application, when some other application pops up a window and steals the focus, so my typing (password) goes to something else. I would like to prevent this, at least when I actively type something in an edit box. I always really hated this on Windows, but I never found a way to prevent this. I started using Ubuntu a while ago, and so far I was able to do everything I wanted, so I thought maybe this is also possible. Thanks in advance!
Install CompizConfig Settings Manager
or via terminal:
Open CompizConfig Settings Manager and go to General -> General options -> Focus and raise behaviour
Change the 'Focus prevention level' from 'Low' to 'Normal'.
As you haven't accepted an answer yet, perhaps using this bug - a minimized always-on-top window to not even put on-demand new windows on top, would help.
(I tried the first comment which set the setting to 'strict' but found this didn't work. I also found a tutorial when I searched this setting, that was trying to make windows steal focus like WindowsOS does(opposite of OP), and he set it to 'strict' to accomplish this, and said 'smart' caused things to NOT steal focus. I tried 'smart' and it worked. I can now type freely into a terminal while programs open and they don't steal focus. Ubuntu 18.04) https://major.io/2015/07/06/allow-new-windows-to-steal-focus-in-gnome-3/#:~:text=Open%20dconf%2Deditor%20and%20navigate,and%20you%20can%20select%20strict.
The best recommendation I have for this issue is using "Always On Top" or "Always Below Other Windows" options for the window you need to remain (un)focused. Just right-click your title bar and check the option. I can promise, that window anyhow, will and/or will not lose focus for anything popping up.
You can also force certain windows to stay on a particular workspace. You could also divert the applications that have frequent notifications to workspace 1 and then operate from workspace 2.
Edit: To address comments, this is a workaround idea that "could" solve the potential problems, and very much affects focus. And comments that follow, the question is not just referring to "general" problems with focus being stolen, it's not even Microsoft Windows they are asking about. ?