Admin Menu in Frontend adds an option “Show admin menu when viewing site” to your profile. You can enable this option and see the admin menu on the public pages.
Also, you can close the admin panel with returning to the recently viewed public page.
This solution may be good for content managers but not for frontend developers because admin menu may change the design of some themes.
On this video demonstration you can see how to show admin menu in frontend, hide the admin menu and close the admin panel.
If you want only “Close admin panel” functionality, you can install Switcher plugin.