I used to be very satisfied with Firefox showing in Windows' task manager as a main process-tree with most of the browser's windows and several distinct processes, each connected to a specific window, that could be terminated separately to de-allocate resources without closing and losing the window itself.
Since last Windows' big update I only see a single process tree, but I can't terminate its "sub-processes" without having the whole program close. I can still terminate processes independently from Windows' resource monitor, but from there there is no way to distinguish the main process tree (which would close the whole program if terminated), making that route not viable.
These are few keys from
about:support that show multiprocessing is activated:
Multiprocess Windows 69/69 (Enabled by default) Web Content Processes 5/4 Multi-process staged rollout 3.05
NOTICE, that I can terminate some of the sub-processes in a way similar to what I intend to, but terminating one of them will reset several windows instead of only one and, most importantly, I can't distinguish the main Firefox process from the others and closing that one will close the whole program (while closing the other ones just "resets" a single windows).
This is a picture of the current situation, I'd expect those sub-processes each to have an independent process and the main process to keep those windows that don't have resources allocated to them.
This is a picture of how a window is supposed to look after the related process has been terminated.
Is there something I can do to revert to a situation where I can de-allocate each Firefox's window resources independently from the main process?