[Evolution] Changing active pane highlighting

["Gilchrist, Michael Aaron" <mikeg utk edu>]

Is there a way change the settings for how the currently active pane within the
Mail is highlighted? When the "Folder List" or "To Do" panes are active, I can
see a slight change in the highlighted folder or to do item (see 
https://pasteboard.co/KfzjGaG.png). In contrast, it's impossible for me to tell
when the "Message List" and "Preview" panes are active (see 
https://pasteboard.co/KfziIqQ.png). 

Is there a way to make this highlighting more apparent?

Much obliged for any help.

Mike