William asked me to resubmit. This patch highlights the currently-selected item in emum lists.
It changes them from the behavior shown at the top-left here to top-right. The hover highlight is lower intensity, the currently-selected gets the stronger highlight. Overall the behavior matches that found throughout the interface, including toggle buttons, Outliner, etc.
The four samples in the bottom of the image are other ideas we have tried and explored. None of the other options worked as well to show the most important part: what is already selected. The multiple columns of icons were distracting. And the right-side indications didn't work at all with multicolumn lists.
Following is another capture, showing the Editor list: