Open new pages in new windows not working.

Hi!

I have my tabs options set to "Open pages in tabs instead of windows - NEVER".

I suppose that means that every single new page would be opened in a new Safari window. But that does't happen.

From time to time that works as expected but the other times safari tries to open a new page instead of the already existing tab, basically it navigates you away from the tab already opened.

Is there a way to fix that?

OSX 10.10.4 (14E26a)

MacBook Pro (Retina, 15-inch, Late 2013)