Scapple & El Capitan's Split Screen

For some reason, El Capitan’s split screen function doesn’t let me pick Scapple as the second application for split screen when I’ve clicked and held on the full screen button on another app. Is there a way to make Scapple share a split full screen with another app, or are there plans to enable this feature if there isn’t a way?

Split Screen does work, well it works with preview and Safari.

Works for me too.

Revisiting this issue, I can’t replicate the problem. It must have been a bug with the other application, whatever it was.