This is a request for a change with the UI-
When making changes to a material, the preview window completely clears the shader, momentarily showing the default checker material, before displaying the updated results.
It would be helpful if the editor simply waited for the new shader results to finish compiling before showing any changes in the preview window, so that the artist could more clearly see the difference that the change has. It’s harder to tell when there is a blue and white checker material (with different specular, etc) flashing in between the two things being compared.