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The problem is that the 1st time I do the action the method kind of works as expected. It opens a new browser tab with the proper content. But the 2nd time I do the same action, 2 tabs are opened, and 3 the third time, and so on.
Ok, again I'm answering myself.
What I was doing was creating the BrowserWindowOpener, and applying its .extend() method, several times, that is, dynamically, calling to the method that does it each time I was applying the click.
Now I understand that I must create the opener and extending it just one time and maybe change its contents later.