[PLUG] obs-studio recording from a captured window

[Rich Shepard]

Two days ago I posted a message on the obs project's forum; there's been no
reply to it. I'm sure that I've missed a simple step and someone here will
see just what it is. I can post a screenshot on file convoy if that would
help.

I want to record a tutorial with the video being a PDF file of slides and
the file displayed by 'impressive' in an 800x600 window. OBS-studio sees the
window as a source but does not display it for recording; there's only a
smaller red bordered box in the obs window.

These are my obs settings:

Video:  Base (canvas) resolution: 1920x1080
         Output (scaled) resolution: 1920x1080
         Downscale filter: Lanczos
         Integer FPS varlue: 30

Output: Output mode: Advanced
         Recording:
           Type: Standard
           Recording path: /path/to/the/PDF/file
           Recording format: mp4
           Audio track: 1

Sources (named scene: Window capture (Xcomposite)
                       Audio input capture: PulseAudio

I learned that impressive needs to be displayed in obs' virtual desktop or
it's not seen as a source. So I start impressive and move it to that v.d.

I have window capture as a source and can select the application in the list
of windows to capture. This puts an empty box with a red boarder in the obs
display. I'm not sure I have the base and capture sizes correct. My monitor
resolution is 1280x1024 and the PDF slides are in an 800x600 window.

How do I see what obs has captured? And where do I start recording since I
see on the bottom right menu an item to start streaming but not recording?

TIA,

Rich