do app tabs in 4.0 allow a website to continuously access my browser?
For example, if I keep my bank website in an app tab, does that mean that my browser still is open if I have an app tab (even after closing the active tab for that website)?
Also, does closing an active tab (just a regular one, not an app tab) have the same effect as closing the browser with respect to security? There are several sites, after I log out, that recommend closing my browser for security purposes. Does closing the tab do the same thing (even if I keep my browser open for other surfing)?
ప్రత్యుత్తరాలన్నీ (1)
You need to close and restart Firefox if you want to remove session cookies. Closing active tabs is not enough. If you keep pages open in App Tabs then Firefox 4 saves cookies as part of session data and that data is being restored on a next start.
You can set the pref browser.sessionstore.privacy_level to 2 (never) or 1 (non-HTTPS, default in Firefox 3 versions) on the about:config page to disable saving cookies via session restore.