Why do I continually have to sign in?

First, I thought Creative Cloud could be used without internet access, all the time?  If I have to continually sign in, everytime I start the app, it looks like internet is mandatory.  Is it?

Second, why do I have to sign in so often?  Sometimes the app makes me sign in 2 or 3 times before I can even start.  I can open the app, load an image for instance, and when I begin to edit, the app shrinks and asks me to login first.  After logging in, I have to reload the image.  This is very annoying.

Any idea how to prevent this?  I'm not in the trial.  I've paid for the full subscription.

Thanks,