See C++ Slate code of an UMG widget blueprint created in editor?

I want to make an editor tool that has a UI, but I think it would be much easier to design it in UMG, and then just copy/paste the generated Slate code in my new editor window c++ class.

Is this possible?

I’m afraid that’s not possible.

UE reads the definition of UMG widgets from asset files on runtime and calls relevant Slate code on the fly. There’s no intermediate step where there’s C++ code generated from Widget files.