Code review comment for lp:~nick-dedekind/qtmir/multiwindow.configuration

+class ScreenAdapter : public QObject
could this not inherit QScreen?

The config design is good IMO, some things cannot be declarative.

+class ScreenMode : public QObject
http://doc.qt.io/qt-5/qobject.html#Q_GADGET would be lighter.

Overall design looks good IMO.