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As I folowed threads about toolkit abstraction. It includes dialogs and controls and not main editor.
So probably neither 100%QT neither 100%GTK version will be possible. Editor will still be OO toolkit based (which I think is base X11). Meaning redrawing of editor probably won't go trough native QT or GTK canvas.
But fell free to correct me if I'm wrong (it's a long time since I folowed that thread).