Firefox doesn't show toolbar and menu bar in popups by default. So you won't be able to do things like print preview, etc or play around with the url. Pop ups appears by default as in the image below.
To enable it open about config by typing about:config in address bar. "This might void your warranty!" warning page may appear. Click the button "I'll be careful, I promise!", to continue to the about:config page.
In the Search box at the top, type dom.disable_window_open
You will see various options. These value of these options could be toggled between true and false by double clicking the particular option.
The main options are:
Below you would see what happens when you set dom.disable_window_open_feature.menubar to true
In this case the menu bar appears, but the address bar url is read only, as you see it's greyed out. So you cannot edit the url and play around with it (for whatever reasons you want to play around).
Below you would see what happens when you set dom.disable_window_open_feature.toolbar to true
In this case the tabs appear and the address bar url is not greyed out. So you can edit it and play around.
But in this case the menu bar is not present. So you cannot do things like print preview, etc.
Below you would see what happens when you set dom.disable_window_open_feature.menubar and dom.disable_window_open_feature.toolbar both to true
In this case the tabs appear, the address bar url is not greyed out and also the menu bar appears. So all the requirements for this blog post is accomplished.