I wish I was as articulate as you. This is exactly what I mean when I see the not responding messages in Mozilla Thunderbird on Fedora/Gnome.
I would probably be ok if it happened very rarely but it happens all the time. I don't know what to replace it with though. We need to convey the user some way that their clicks and keypresses won't do anything because the application is unresponsive but as a user I dislike the dialog window that comes up and goes away after a few seconds.
I think a notification banner at the top of the window like many browsers do is fine, it doesn't block the user, is still visible, you just leave the behaviour that is the most harmless in this particular case (don't lose the changes in the case of notepad++).
I would probably be ok if it happened very rarely but it happens all the time. I don't know what to replace it with though. We need to convey the user some way that their clicks and keypresses won't do anything because the application is unresponsive but as a user I dislike the dialog window that comes up and goes away after a few seconds.