I think it would be very handy for the GX corner to close when all other tabs are closed. This would make it a lot easier to manage multiple windows, switch tabs between windows and use two windows in split screen.
Maybe this could be implemented so that if there is only one Opera GX window open, GX corner stays open so that opera doesn't close totally in that case.

A feature to move all selected tabs together in the tab list would be greatly appreciated. Currently if you select multiple tabs in opera GX and drag one, only one moves around. If all of the selected tabs moved too, it would make it a lot easier to manage large numbers of tabs.