Interesting observation in JS

Hi Team,
In this link below:

if I print the output of following -
console.log(workWindow.tabOpen());

I get two “new tab”
but some for this : console.log(videoWindow.tabOpen());
I get only one “new tab”

If I create my own like this:
var newWin = new Window();

console.log(newWin.tabOpen());
I get one “new tab”

Can anyone please explain why two " new tab" are showing up for those ?

Sorry guys, I found the location where the function was called twice. My bad.