If so why? What are your use cases?
Normally, I don’t.
I can imagine this practical use case: One almost fullscreen window you use to view some data. One almost completely obscured editor window behind it where you take notes.
With that arrangement, you can click the editor window without it popping in front to (blindly) take a note without obscuring any part of the ‘data’ window.
Maybe not the the most common use case, but one nonetheless.
I use it, because I’m an ex-Amiga user and got used to windows remaining where they are in the z order when you interact with them. I also use ‘accept first click’ to replicate the Amiga OS behaviour.
One use case is copying files where the source file is in a tracker window partially behind another tracker window you want to copy to. You click and drag the file to copy to the destination without the source window moving to the front and obscuring the destination. Not so much a problem these days with bigger screens, but I still prefer the way this works.
I often do something similar to the example from @humdinger , but a full screen terminal window where you bring a browser up in front to copy some commands etc. You don’t want to keep moving the browser window back to the front again when copy/pasting.
I do out of habit…to ensure what window I what to interact with.
What is ‘click in focus’?
When you do not select “accept first click”, you have to select the window you want to interact with to make it get the focus.
I understand that “accept first click” can be useful for people who are working with a system and are used to it. It certainly allows to save a bit of time.
Personaly, I don’t like to accept first click because it is source of errors. i.e If you leave the screen to do something else, when you’re back the screensaver started. Then, if you click accidentally to get your desktop back, you don’t know what you have done.
I also agree that in some situations, it is more annoying than helpful.
I think “accept first click” is an option to enable only when you feel confident with the interface and are ready to accept consequences of an accidental click. So not as default.
And every time new window is annoying too