red box in window

Hello! New user here with weird problem. When finishing a small project yesterday a small red box appeared in window. I clicked and right clicked and tried to figure it out....no go. What was it and what does it mean and how to get rid of it?

Thanks,
Klmadrine

In what window? Can you post a screen capture?

If it was in the Viewer, that simply means you zoomed in on the Viewer. The red box shows which part of the full video frame you're seeing. Make the Viewer active (click in the pane once) and use Shkft-Z for "Fit To Window". You'll see the full video frame, and the red box (if that is what your issue actually is) goes away.

That one is the replacement for scroll bars in case your view isn't set to "Fit"

-Andreas