I have just had a board come back from manufacture where the top layer is joined to an internal layer around a through plated milling slot. It seems there is no keepout layer for the internal layers when laying out a board or defining a component package. It is also not picked up on a DRC check. I have been using EAGLE for over 10 years and this is the first time the DRC has let me down. Does anyone know how to put a slot in the board and have it treated like a pad so that it is isolated from the internal layers if it is on a different net? I can provide a test .SCH and .BRD file to demonstrate if required.
John (who is about to do some delicate Dremmel work)