Mapping transparency help please

I'm trying to get a meshed fence to work.

This is what I want and how it appears, sometimes, in the part.

This is what I get in the assembly.

...and then after I view this and switch back to part I get this in the part. In order to get to go back to the first picture all I have to do is to edit appearance.

What am I doing wrong?

SolidworksPhotoview 360