Welcome screen acts like a separate window to an extent

On OS X with qt-enterprise-mac-x64-android-ios-5.4.0-rc_2014-11-12_12-49-09-87 pre-release, you can see something strange like this:

1) start creator
2) go to full-screen mode
3) ⌘Q to quit
4) start creator again
5) it will start in fullscreen mode, but you will see the zoom animation happen twice

On Linux, I saw something which might be related, when running my own build of creator in a weston/wayland session: the welcome screen is in its own decorated window. The two windows are on top of each other but can be moved to different positions. It doesn't matter whether you start it up fullscreen or not, on wayland. When you switch modes (say to the Edit mode) the extra window goes away, and comes back if you go back to Welcome mode.