i can't do it....here's a simple example of a base plan showing EXISTING and DEMOLISH interior walls - 1 & 2,respectively.
in the layer combination, i added a 'base plan' to show all the existing walls (1).
then i changed wall (2) into dashed line and empty fill and change layer to DEMO and added 'new' to layer combination.
when i switched to 'base plan' in the layer combo, existing wall at (2) is not there.
this sounds simple to many of you but i am just not getting it!
HELP