Automatic restore of IDE does not work

After updating to PyCharm 2017.2.3 (and from Community Edition to Student License) the IDE does not restore the last view on my project (IDE layout, opened files, etc.). The "workspace.xml" file seems to be missing any reference to my opened files.

Are there any settings that control what is saved and what is restored? Can I check in "workspace.xml" what is saved?

Thanks

Pierre