Color Fill & Conditional Formatting Problem

I am trying to mark duplicates in a single column of a table. I tried the conditional formatting feature to achieve the goal. While it changes the font color it does not apply the color fill as define. In trying to determine the issue I've come to realize I have to double click the color fill button in order to directly apply color to any cell outside of the conditional formatting functions. I checked that all conditional formatting rules are cleared and I've checked that I am not using the Windows High Contrast features. Any suggestions???

If you "Go Advanced" and upload your .xlsx file (or a simple version thereof) it may make it easier to help you.

Thanks for the reply... The one thing I hadn't tried was copying everything to a new spreadsheet. Surprise surprise that fixed what was ailing my efforts. The problem I have is now I don't know what caused the issue to begin with sometimes I hate computers.

Happens that way sometimes. My little laptop started acting up just after I wrote that reply, so I shut it down, walked away for 30 min or so, and when I came back it was working fine. Hope you have a good day.