Imagine you have several US States on a map showing sales over time. On separate line chart, you want to represent this, but it's 1) too cluttered if you include all 50 states, or 2) completely aggregated if you aggregate all 50 lines.
It would be nice if all 50 States were aggregated to 1 line when "no data selected" in data limited, but when a user marks some states, that 1 line gets split into multiple to represent each state.
There are various other scenarios where this comes up as wel