Hi @wztdream,
Apologies for the delay, just wanted to provide an update here - I looked into this and we do not support the step slider on wandb.plot.bar as we do on images, since they work on different underlying mechanisms. That does sound like a great feature request though, and I am creating a feature request to enable this.
For now, I would suggest using wandb.Image to get a step slider based bar graph.
Thanks,
Ramit