Mozilla Firefox with multi tab feature already a while. With multi tab feature enable user to open many pages just in one windows. That’s for user experience and friendliness. But do you know that you can open Firefox browser inside Firefox tab? Yes you can do it easily.
Here is the steps to open another Firefox browser inside Firefox tab:
1. Make a new blank tab (you can use Ctrl+T)
2. Type this into the toolbar:
chrome://browser/content/browser.xul
3. And boom: you can see as the screen shot below: