The new Studio Project Wizard has a few behaviors that are not really user-friendly:
For instance, if you start by defining new ad-hoc file type settings and later on notice that the source language of your project still needs to be changed, then you will lose all your work on defining the ad-hoc file type settings without any warning from Studio. Studio should have some kind of warning before throwing away all your work on project settings before allowing you to change the source language of your project.
Currently there is no warning.