I recently installed the newest linux version of gnatstudio and the project properties option seems to be missing.
This is normal. Look at the changelog.
I guess the idea is that the truth is in the GPR file, not in the screen of this menu which could cause more problems than anything else.
To keep this option, you would have had to parse the GPR file towards the screen and vice-versa, which would have led (without a doubt) to āalterationsā of GPR filesā¦