UE4 stream with OBS (SLOBS) problem

hello friends.
how to stream UE4 process (EU4EDITOR.EXE) in OBS in window/game mode? Its possible?
i see its not important problem, all people stream/capture in Monitor mode,but for streaming Full Monitor not good (folders, browser, txt files,etc).

all streamer use monitor capture for UE4 streams.

here similar problems:

https://www.reddit.com/r/Twitch/comments/8v44xf/streamlabs_help_black_screen/

any solution?

Open a new viewport (Window -> Viewports) and set OBS or SLOBS to capture JUST that window. Just tested it myself, works like a charm.

freeze after first frame + switch window to tooltips/alerts (