A column formatter function can be called in various modes, depending on the situation:

• regular
• creating a grouping row
• creating a footer row
• sorting
• etc.

In each of the modes, the options and rowObject parameters have different stuff in them, and the cellvalue can differ, as well. It would be helpful to have an item in the options param that identifies the mode, rather than having to guess at it, or derive it from other properties in convoluted ways.