It seems that I found the source of the problem: I use PC monitor as an output, and tv box is connected to the monitor’s DVI input port via HDMI->DVI adapter. When I connect the box to another input port on the same monitor - a full HDMI, things work. So it seems that the problem is caused by the adapter.
Since NG works properly with this HDMI->DVI adapter, does it means that NE misses some driver and that the problem can be fixed in the future?
Screenshot of NE usage via the adapter:
