Hello Mike,
Please excuse my reply in English - I cannot write French though I can mostly understand your post.
I am not sure why your settings are not saved - the ruler always stores the latest settings in a file in your installation directory called "dat". If the ruler sees "dat" in the current directory, it loads the last-saved values from it, if not, it uses defaults.
One explanation could be if the installation directory is read-only, "dat" will never be created and the ruler will always start with the defaults. Another possible explanation could be that you are running the programme directly from the zip file without extracting/unzipping it? (another user did so and had the same problem) If so, "dat" would not be created and it would always start with defaults.
Hope this helps resolve the issue - I wrote the programme because no dedicated tool seemed quick and simple to me. Let me know at
onscreenruler@gmail.comJohn