Animated resize of window not animated.

I am developing a journalling system using C++ and QML (QtQuick 2) for desktop. Altough it doesn't matter, the server backend is written using the Crystal language.

Following the design documents, the application is supposed to resize itself, once it is done loading settings, etc..

For the sake of this, I created 2 states ('loading' and 'default'). The 'loading'-state, sets the window's size to 300 by 300, on the other hand, the default state sets it to 1024 by 768 pixels (depending, wether user's have set any other options). I tried to leverage the 'NumberAnimation'-Item, which ultimately fails in this use case.

The window does resize, but jerkily in 2 or 3 "step in between".

I don't know, wether this unintented behavior, i.e. a bug, or an restriction imposed by the Mac OS X window manager.

Cheers, Julien

See my example within the attachments.