Problem logout from outlook.com accounts

I have two outlook accounts connected to X-notifier. When I login to the second (not default) account using the X-notifier link, I am able to use it normally. However, when I logout, a new tab (remains empty) opens, while I remain signed in in the first tab.

Login and logout on the default outlook account works fine once (per session), but any subsequent  logout results in the inability to logout too (as described above).

Any clue what happens here and how to correct this?

Using Firefox 35, X-notifier 3.5.4, both on Win7 (both 32 and 64bit), and Ubuntu 14.04 (both 32 and 64 bit).