All debugger-window variables are same color (no modified color)

A few weeks ago, I noticed that the modified variables in the debugger window are all the same color: light blue. Before, this was the case for only the modified variable from the previous debugger step. Is there a way to get this back to only changing the recently modified variable to blue (or a different color) so that I can quickly find the variable in the debugger window? Here's a screenshot:

As you can see, all the variables besides the watch variable ($_SERVER['PATH_INFO']) is light blue. This happens after the first variable is created / modified in the last debugger step. I tried changing the color scheme from light → intelliJ Light → Darcula → intelliJ light. But, no luck.