Anyway for material preview not go default grey when changing a value?

Im new to UE4 so please excuse my ignorance, but I have an issue with seeing changes to my material. Whenever I make a change in the material editor it sends the preview to a blank material rather than switching from my last change to the new change (like if I were to change from blue to red, rather than just go BLUE → RED it goes BLUE → DEFAULT GREY → RED) . This is very frustrating because I can never really see how much changed other than OBVIOUS changes.

I do know about material instancing but that’s a rather slow process rather than being able to iterate quickly on the fly.