Just an FYI- It is a good idea to make sure you are not in the middle
of routing a trace when you save a design (PDB). The fact that the
trace is selected in route mode is not captured in the PDB file. As a
result, if the application crashes and you need to replay the
transcript it will start off with a route command. Since nothing is
selected (like it was when you saved) the route command will simply
try to route whatever other trace happens to be located nearby.

Greg