Hi @Drakmire ,
If you click on a Color that you can change, you get this:
,
and now you can choose the Eyedropper. If you just hover over that Color, you can press E to activate that Eyedropper. That is what the shortcut does.
The Eyedropper uses what Color it ‘sees’, so in Rendered Mode, what you want should work (if I understand you correctly).