Picking the right values for charting

Hi there,
I am currently in the works of building up relevant graphs in my OH2 installation but I am struggling to pick the right item for graphing. For example, when I try to visualize certain power meter values from a given dimmer, I can’t tell one meter from another. As you can see in the attached screen dump, they all look the same.

If I go to Configuration -> Items, I can see the very same items there but I can’t change the label do a more unique name that is easy to identify. Seems like it should be possible though. What is it that I am missing?