Okay, I've done some research and think I understand how "ObjLibrary" works as well as the difference between a cube inserted from the solids panel and a cube inserted from "ObjLibrary", which I never used.
Currently, I am rewriting a file (in French) "Introduction to MoI3D" from the "en" and "fr" files with the addition of screenshots of the small dialog boxes that appear at the top left, in the process of creation of objects. As well as a chapter that I called "tips and tricks" where I added, for example, what is attached below.
Well, this is my way of appropriating MoI3D (undoubtedly a professional distortion!).

Watching Parel's latest video (http://moi3d.com/forum/index.php?webtag=MOI&msg=10267.25), I see that "draw curve and" draw solid "are grouped together in one tab in two parts. I would like to have this organization. I had already told Michael the solid tab closed by default, but this arrangement suits me even better. Okay, I'll look at the relevant file, but I'm pretty sure I don't have the capacity to do the modification by myself, so if anyone knows, please tell me how to do it.
-Zooen

Hi Zooen, maybe try this:
http://moi3d.com/forum/index.php?webtag=MOI&msg=8064.8

- Michael

Merci, Thanks!

-Zooen