The blueprint parent select dialog is broke in the master branch. This commit is the one that broke it. It seems like the class buttons and text are not being rendered. To build that reversion you need this patch. This video will show you what I am talking about. The video was originally about a different issue but it shows the empty class selections in the class selector dialog. I don’t know enough about slate, or at all, to try and track this one down by my self.
Hey -
Sorry for the delayed response. Looking at the video you posted I do not see the same behavior when creating a blueprint in the current master branch. Let us know if see this happening on the latest build.
Cheers