So, is saving works fine now?
You can find out how many objects you need to add for the file size to reach 1Mb, I think a lot. And probably nothing awful will happen, but the file may take a bit longer to save - there will be a delay before "Save as" dialog appears.
Yes for the current test I can pretty much add many more objects without the weird hidden-saving-window problem (btw it never appeared before, even if I wait 10 minutes) it just... wasn't there but ANYWAY that's a HUGE progress, THANK YOU SO MUCH Sensei Dop! :)
Just to be sure I'll keep on testing, tweaking more things instead of just placing objects over the screen while one eye on the other screen with the console open.
Maybe I should somehow... LOCK any mouse interactivity while saving and put some "SAVING... Please Wait " message on the screen.
I'm not sure how to LOCK all the mouse interactions or WHERE to insert such event, but do you think this idea could be useful or just waste of time / cosmetics, your opinion matters a lot! (I'm not just asking).
I'll keep updating if I'll find out something weird.. who knows, that's why I must test before I proceed.