A backside of your mod is that if you dont place blueprints in the belts, you cannot recover them from inventory being unable to choose them from the item list selection from toolbelts and having no chances to take them as item in inventory.
Any idea?
Can happen that when you have in hand a blueprint you press a wrong key, like a number or Q key and transfer it in inventory without have the chance to place it in toolbelt. To me even often because when the phone ring I have to drop my cordless keyboard almost instantly and happen that some keys are accidentally pressed in the process...
Any idea on how to solve this "issue"?

I'm not sure the ideal way to solve this. Can you still right-click open the blueprint and use the copy command to put it back into your toolbar?

I've added this to my TODO list --- thank you for reporting 🧡

I've found it, but I've a lot of blueprint duplicates that I've to delete. :P
When you've in your inventory 80 blueprints or deconstruction tools, you've to trash a lot of them or you're submerged by "bluepaper"! XD