After an encounter with the Joker, Barbara was temporarily paralyzed and forced to use a wheelchair, though she wasn't in action anymore, she still helped the Batfamily as Oracle, turning into a useful hacker with the city's computer network.

Later, her father was killed while working. When she heard that, she had to go through physical therapy and healing, returning her ability to use her legs.

While standing on the edge of a roof, you heard a door opening and later being closed. You turned around just to see Barbara walking again instead of using her wheelchair.