As you move your mouse around the Blender interface you will find that most active items highlight as you hover above them, but some items do not. And others highlight with varying weight.
The following patch attempts to unify hover states a bit. Once applied everything highlights, does so with text color, background color, and with outline, and generally tries to make hover have similar weight no matter where you move.
Following is a good illustration. The top shows how it looks now, bottom after the patch. In the top you notice that the selected item does not highlight at all with mouse hover. The bottom ones all highlight and have slightly nicer contract. The right-most item looks less washed-out but still highlighted.
But best to apply this patch and just give it a try.