Itunes on mac - why are purchased films not displayed in films-library anymore - How to watch without downloading

I used to see all my purchased films in iTunes on my mac (in Library - films), regardless whether they were downloaded or not, and I was able to watch movies without the need to download them, which is what I still want to do. It appears that no films are displayed in my library-films in iTunes on my mac, while I purchased dozens of films. What should I do? I do not want to download any movie on my mac, but I want to be able to watch purchased movies on my mac, without downloading them. It was possible, I have just noticed that it does not work anymore. Any hint ?