If a screenshot is created when a Monosnap editor window is open, the new screenshot overwrites the current window.
Screenshots can be added to an existing window if the + button is clicked on an open window, but there’s no way I’m aware of to have multiple editor windows open at the same time.
Having the option to create a new editor window (and leave any open editor windows intact) would be useful.
We plan to add this feature with the new editor. However, the exact release date isn’t appointed yet.