LightmassVolume no yellow box built 0%

Hi All,

When i drag a lightmassVolume into my project, i noticed that the yellow box around it has dissapeared.
Also i think this is the reason why my project stops at 0% lighting build.
When i add a new level to this project (empty one) with a sphere and a lightmass volume (no yellow box) it is also stuck at 0% lighting build.

When i start a new project the lightmass volume does have a yellow box AND the lighting DOES build imediately.

I’m confused now forover more than a week now how to solve this.

I can’t find anything about a dissapeared yellow box around the lightmassvolume on the internet.

I’m working with UE4.15.1. and also in 4.14 the box is not there.

any suggestions?