Habmin 2 not properly working

Dear community,

prior migrating my existing 1.8.x Openhab setup to 2.0, I wanted to thoroughly go through all the configurations, setup possibilites etc - simply to not screw anything up.

So I did a fresh and clean install of Openhab 2.0 (not package based, downloaded the ZIP File) on a dedicated fresh VM - and alloverall, it seems to be quite reliable, expect for one thing: Habmin2 seems to be screwed up.

My major target would be the graphical rules editor (even though graphing would be nice as well, sitemaps a big plus…), but the rules editor is my major concern.

Starting with that strange big “image missing” - icon in the lower right corner, I can’t actually work with the designer at all.
Sometimes at least files are created in the rules folder, but adopting them in the browser seems to be dysfunctional.

Has anyone of you already experienced something similar with Habmin2?

Thanks a lot in advance

Nobody any idea?