Most of this is certainly possible with Qt. KDE Plasma ships with a global menu and Qt >= 5.7 exports its menus to DBus, so that covers those. As for other UI e

Most of this is certainly possible with Qt. KDE Plasma ships with a global menu and Qt >= 5.7 exports its menus to DBus, so that covers those. As for other UI elements (buttons, etc.) I'm not sure - I've seen it done through dll* injection, but I don't know it there's a cleaner way.