Open event is not triggered with popup window

I am developing a Firefox add-on using Add-on SDK tool. I am doing something as soon as a tab is opened. I registered for all tab’s event( open,ready,close).

var tabs = require(“sdk/tabs”);
tabs.on(“open”,openTab);
tabs.on(“ready”,readyTab);
tabs.on(“close”,closeTab);
And i have respective functions for each event Listener. Problem which i am facing is some of the webpages opened in a new window. For those web pages none of the event Listener is firing. Please help me out in this.

By debugging the following function at resource://gre/modules/commonjs/sdk/tabs/tabs-firefox.js

// Detect tabs in new windows windowObserver.on(‘open’, domWindow => {

if (!isBrowser(domWindow) || ignoreWindow(domWindow))
return;
let window = null;
try {
modelFor(domWindow);
}
catch (e) { }
for (let tabElement of getTabs(domWindow)) {
addWindowTab(window, tabElement);
}
});

When I go to the page “http://www.yourhtmlsource.com/javascript/popupwindows.html”, then go to the line “Try it here: » Pop it” and lick on “Pop it”, a new popup window appeared, and I found that the function isBrowser(domWindow) always returns FALSE with the popup window.

Please help me the way to make isBrowser(domWindow) return TRUE.