Illustrator Graphic Styles, Style has no content

hi people,

I have a problem with graphic styles in illustrator.  I'm. trying tocreate a new graphic style from text, but the style stays empty. I tried drag and drop, creating an empty style and adding the cfreated one to it (by pressign alt) and searched the web but can't fiend a solution to this problem.

The selected graphic style in the image should be the text I created. As you can see even the miniature pic is stating it's emptiness.

Drag and drop worked fine before. Can anyone help me to fix this?

Best wishes