Material List Components Re-appearing

[johnnydp]

After drawing exterior walls in my small plan, I edited the components to remove the batt insulation from the Wall Type dialog and then specified rigid foam boards.  Now when I create a new materials list, the foam board appears on my materials list, but also the batt insulation is still showing up in the list.  I have searched everywhere in the floor plan and can't find any trace of batt insulation.  Why is the batt insulation still appearing as before in the newly created material list?