Layer toggler and general workflow

Being able to assigning elements to layers would be extremely helpful. I would also like to add that if elements in layers could be toggled on and off, the next thing I would want to see would be a basic work flow. Assign layers to a step-by step work flow. Have the comments associated with the active layer(s). Another nice feature would be to have clickable/interactive areas that could be activated to jump to different sections in the workflow to give mockups a very basic level of interactivity and workflow understanding.

I believe these features would make Balsamiq a much more powerful tool.