Performance freeze in Windows Task Manager

I don’t know if it’s a bug or a feature (*) but the Windows Task Manager doesn’t seem to refresh its graphs when we are moving its window. It’s barely noticeable when you usually move it (**) but you can spot this behaviour when one of your other windows is freezing.

Freezing performance graphs - Windows
(larger screenshot)

(*) I know this post is nearly useless but I’m tired of waiting for this freezing software …
(**) I guess it refreshes its graphs between window movements: a human being can barely notice if Windows stops moving the window for 1/100th of second to refresh