Project is updated once I click on "Play"
I've got several projects on which each time I click on "Play" then music starts but the project is updated. When I want to close the project the system asks me if I want to save my changes. If I open a project and just play music, without doing any change, I've got the same message. This problem is really annoying. I don't have that issues for other projects and I can't what's the difference. Is there any setting for this behavior?