Key, Safari and JavaScript Blocker issue

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Key, Safari and JavaScript Blocker issue

I'm using the JavaScript Blocker extention for Safari on OS X. But it's always weirdly ends up blocking F-Secure Key. Eventhough, as an example on Twitter there is only 2 scripts listed, one blocked (Google Analytics) and one accepted (abs.twimg.com). I can't understand why, but it stops F-Secure Key from filling in usernames and passwords. And I've looking around in the settings, and I can't  find or where or what the problem is. 

 

I could just disable the extention obviously, then it works. But I really like being able to block script or services I don't "want". 

 

Anyone with a big tech brain, who care to explain what I don't seem to understand. Thanks.