Slade and "remove unused patches/textures"

[plums]

How are you supposed to use these? What I'd like to do is take a texture pack and remove only the new textures from that pack that aren't used. I don't want them to erase entries that come from doom2.wad or whatever iwad is being used, because that seems to cause problems trying to run the map.

If this is a bug I'll file it on the issue tracker, but I feel like it's probably just user error...