QuoteOr are you creating stuff with the object tool? If you are creating them, they will be created in the level you are viewing. CRTL 0 gets you to level 0. Create your objects there.
Yes, I was creating a polygone with the object tool, yes I was viewing the image at level 0 (I'm always at level 0), but with a high zoom factor for more accuracy. Nevertheless, I discovered later that the object has been created for level 1.
I didn't have the warning set, it was unchecked by default as I discovered later.