I wish if there would be a --hide-opera-button or --disable-opera-button command line switch... I wonder if someone already filed this as a bug? They don't necessarily need to implement a KDE or GTK3 menu, just have a normal opera menu without the button, invoked by pressing Alt or Alt-F.

I know there are people who are not using a keyboard (such as using Opera on a TV) but there are also people who are using Opera with a keyboard, but not using Unity and don't like the Opera menu button and would like to save screen real estate. I miss some of these features from Opera 12...