What overlay are you using?

Like theme? I am using Reboot. 

Yes but reboot comes with a selection of overlays and I need to know which one you are using so I can test with it. See the themes section and note the overlay in use.

Ah looks like I am on minimal. Might that be the issue? 

It’s not the problem – the lack of a clear styling rule seems to be the problem.
Normally the background to the row would be coloured differently. For minimal that would normally just be a grey of some hue. I will open a ticket to get it changed and come back and post what you can do to correct it.

Actually it looks like it runs a little deeper than just that. So will take a little longer. But working it.

Yellow Swordfish said
Actually it looks like it runs a little deeper than just that. So will take a little longer. But working it.  

Thanks. In the meantime I was able to style the A for spPMUnread but that just highlights the one cell. I couldn’t get it to work for the whole row

.spPmUnread  A {background:#fffae6; border:1px solid black;}