@User: Running drc(full) style while doing layout is horribly laggy. If you're patching up standard cell routing, then use "drc style drc(routing)" which runs only the basic metal rules. Then once in a while you can switch to "drc style drc(full)", select the entire top level, and do "drc check" and wait for it to finish, then go back to "drc style drc(routing)".