Violation controls
When a circuit board document is open, a menu of violation controls is added to the navigation bar:

These controls provide options for the interaction between a route you are tracing and other nearby routes and vias.
Ignore violators
A new route crosses over any existing routes.
Push violators
A new route pushes existing routes aside, but maintains connectivity.

Walkaround violators
A new route can wrap around existing routes and components, but not push them.

Push vias
A new route can push vias out of the way.
