3ds Max Modeling :: Civil View Yellow Road Arrows

3DS Max Design 2014 I am trying to get shaded Yellow road arrow markings. I added the markings to the resource kit .. (Diffuse and Opcaity using same image file)
 
When first used they look correct..

 then with some editing to the model and many opens later the image is replaced by a grey block

this is what it looks like in shaded viewport, but still renders correctly
 
we dont always have time to render to file, we capture screen video. Is there a way to fix this? to get the yellow arrow in shaded viewport - permanently.