X-notifier has separate session manager in it to access accounts in background.
* When you disable 'Multiple login',
If you click account in XN, XN copy cookies to browser.
* When you enable 'Multiple login',
If you click default account in XN, XN copy cookies to browser.
If you click non-default account, XN make browser to use XN's session manager.
This will be displayed as a 'underline' in tab title.