When I was using Konqueror as my file browser today, I got all click-y and accidentally lost my menu. My entire menu was gone. Right-clicking gave me numerous options, including enabling toolbars. However, they didn't work (the menu is is not a toolbar, it's a menu bar). Apparently this syntactical nitpicking makes a difference.
Quick internet search: CTRL + M fixes it.
I wonder if there's a way to enable it with a mouse?