Former versions of Firefox browser for windows would treat closing the firefox windows as exiting the app. However in the current version, closing the windows does not appear to perform the actions (such as clear cookies, site data, and history) that should occur when closing the browser. For example, I closed the browser window (X at top right of window) with a gmail account logged in and displaying the inbox. When I reopened Firefox, it did not go to my start url (gmail login), instead, it returned to my email inbox, and the email was active - logged in. This seems like a security problem to me. My settings specify: Delete cookies and site data when firefox is closed Clear history when Firefox closes I have no saved passwords in Firefox