Thanks for the additional info milkywaif! I've finally been able to reproduce the flicker over here and I'll have it fixed for the next v3 beta.

It was tricky to reproduce because under certain timing conditions with UI loading events it would also not happen (even when not maximized or full screen). In order for it to happen a certain piece of the UI layout code had to finish while the main window was still hidden.

It's an easy one line fix, thanks for reporting it.

- Michael