In Physion, the UI has three main sections with the top being for transients and the bottom being for tonal, and there are also labels for what portion is Transient vs Tonal. The Transient and Tonal portions are what the colors actually are is generally less important.
Originally, SplitEQ was using the same color scheme as Physion, but as we worked on the plugin’s UI more, we found that we felt more and more strongly that the transient color should feel more active than the tonal color.
SplitEQ has different design constraints than Physion because the colors overlap all the time on the plot both with handles and curves (and without labels which would be cumbersome on the plot), so having transients feel slightly more prominent visually made sense. Additionally, you have a “both” color in the UI, so the Transient and Tonal colors have to work with that as well.
We made the decision with the knowledge that it might be a little confusing to use both at the same time, but felt that it was important to make the decision based on what we thought was better for the new plugin. We will probably update Physion’s UI at some point to harmonize the two look and feels.