[[APh] Auto-crop an image (to crop out single colour backgrounds)]

In Affinity Photo, is it possible to crop an image automatically, like GIMP's auto-crop feature?

 

I'm editing screenshots of an application (see the attached) - I take these with OS X's screenshot feature, roughly dragging around the application window, then want to crop it to retain just the window - removing the dark grey bit in the attached example. The background's all the same colour. GIMP's auto-crop feature removes a same-colour border from an image. Does Affinity Photo having anything similar, or do I have to use the crop tool and select the application window by hand?

 

Thanks.