How to prevent popup when moving mouse to north over the Firefox bookmark toolbar?

How to prevent popup when moving mouse to north over the Firefox bookmark toolbar?

Lets start with a sample webpage (from a german newsmagazine):


Immediately before and during loading of the web page leave the mouse INSIDE the (Firefox) browser window.
Then after successful loading move the mouse to north over bookmark toolbar.

As you can see a popup (inside the webpage and not as separate Windows window) appears.

How can I prevent this popup?

I tried

  1. $('.sandiego-c-canvas.Campaign__canvas').hide();

but it didn't help.It seems to me that the code is only loaded when I move the mouse over bookmark toolbar.
So I cannot hide it at loading since it does not exist at this time.

Is there a jQuery hide() or .remove() independent from mouse movements?

Thank you