Does Blender continue to work in the background despite "No responding", the blue loading circle and the "milky" picture, and is it worth waiting?

Question

I'm currently trying out the Smart UV Project function and haven't quite got the hang of it yet. After pressing OK in the Smart UV Project window, the blue loading circle of Windows 10 appears. Blender itself seems to have hung up somehow. The second time I press on the Blender window, I get "No responding" at the top of the window bar of the program and the image becomes "milky".

My question is now: Does Blender continue to work in the background despite "No responding", the blue loading circle and the "milky" picture, and is it worth waiting? If this does not work, what alternative do I have?

And why is there actually no loading bar with this function?

Answer 1

Yes indeed it does. No progress bar is because of threading: Blender was expecting the script or whatever to run quickly, or simply can't run multiple threads with the process for whatever reason (EEVEE is an example as Blender cannot multithread OpenGL to EEVEE render and GUI render at the same time), and the GUI updater is waiting for the process to finish.*

*In some rare cases, something could have gone wrong that was also causing the hold-up.