[SOLVED] Which right(s) do I need to copy a template project to a new one

Which version of ProjeQtOR are you using ?

I think you changed some habilitations for the project leader profile (possibly you just changes access modes)
It's difficult to analyse this through forum.

You can tests that default configuration works fine for copy of templates on Demo : demo.projeqtor.org
Connect as Manager (he is a Project Leader).
Go to screen project, apply filter for type "Template" : you see all templates in the DB.
Select any template project : you may not be able to change data of the template, but you can copy it into new projets.
Copy Works.

here is a capture of the access modes as they are by default in ProjeQtOr so that you can compare