I did no scientific research about this, but I think first it was Microsoft with Windows Vista which started to put the menu bar into question for some applications:
- The ribbon replaced the traditional menu bar for their office suite.
- The menu bar is hidden per default in the Internet Explorer and the Windows Explorer. To still be able accessing all commands a kind of menu-button has been added to the toolbar.
Until I tried those applications I've been a strong opponent of those "menu bar violations". But after working a while with both approaches it seems that ribbons work very well for applications with a huge number of commands. I'm not sure whether the Internet Explorer or Google Chrome has been the first browser without menu bar, but as user of Chrome since around two years I was surprised that I never missed the menu bar and liked the well-arranged menu button.
I got the impression that the menu button as replacement works well for applications with quite less commands. In the meantime even Firefox 4 has switched to a default setup where no menu bar is shown; so I asked myself whether this might be an option for Dolphin and simply gave it a try. Since the release of Dolphin with 4.5 I try to strive for a cleaner and less cluttered default setup and now with having no menu bar I think the default setup is quite OK :
It gets move obvious when comparing this with the default setup in 4.5:
Before the complaints "I want my menu bar back" start: Of course it is possible to enable the traditional menu bar :-)
Back to the new default setup of Dolphin. Beside the missing menu bar a lot of smaller updates have been done too:
- The Information Panel on the right is hidden.
- Toolbar items where the icon is sufficient for knowing the command don't have a text. By the way: In 4.7 this can be changed by a simple right-click.
- If the Places Panel is shown (like in both screenshots on the left) the "places selector" left from the Home > Pictures > Wallpapers path is hidden as it is duplicated functionality provided by the Places Panel.
- The Panels are "locked" per default like in Amarok and don't have a headline and two buttons.
- The search bar at the top right has been integrated into the view when executing the "Find" command.
Please note that those points just talk about default settings, no functionality has been taken away. For me it was - and still is - one of the main goals of Dolphin that it is easy and efficient to use without cutting too many features. I somehow like it that despite the added functionality during the last years this is not reflected in additional visual clutter. When looking back at the history of Dolphin screenshots it is somehow funny that for the upcoming 4.7 release Dolphin looks more similar to the old KDE 3 version than the 4.5 version :-)
 Please ignore the current look of the zoom-icons in the bottom-right of the screenshot. They will be replaced by a more decent version created by Nuno before 4.7.