allow the same behaviour when clicking the button as when using keyboard shortcut to preview a page

[vincent-peugnet]

#415 added a very cool feature, but it only works when using the keyboard shortcut. This could better to have the same behavior when clicking the top bar button (the eye button).

As @n-peugnet said:

Later the button could be overriden with javascript to allow the same behaviour

This will need some more JS to remplace the button.