A great idea posted by tkleager.
This is where you can go into your configuration and set up your own positions.
My hesitation allowing you to drag one person into multiple positions is confusion or making things to complex. For example, if you drug someone from Plans to Operations, would that mean you wanted to move that person from one position to another? Or, you wanted that person to be in multiple positions? The complexities get worse if someone remained in the Available list when they were also in an ICS position - someone making a team could put the IC on a field team.
The driving force behind MM's design is an attempt to keep it as easy to use as possible. This is not to say that MM will never have the feature of putting one person in multiple ICS positions, but a very intuitive way to make this a feature will have to be found to make it so.
Mike