You have quite a complex module scenario, and no code is shown, so I can only give general advice. From my experience, the way to handle such things on a Canvas is with the use of tags, you can find tags, rewrite tags, bind to tags, and probably a few other tricks I'm unaware of. You might keep a global variable of what the Canvas's current state is, then addtag( or deltag) to canvas items for markers on what they should do in that state.

Of course this is just brainstorming, and I may be missing the point of your program. However, I would think about how you can incorporate juggling tags into your statefullness.