Comment 148 for bug 239831

(From update of attachment 417026)
>+ // If the previous (or more) test finished with cleaning up the tabs,
>+ // there may be some pending animations. That can cause a failure of
>+ // this tests, so, we should test this in another stack.
>+ setTimeout(doTest, 0);

Tabs are closed synchronously, so I don't think I understand this. What kind of animations are you referring to?