Decontaminate Color greyed out

I did a select and mask on a project I am working and when I went to hit the decontaminate color box as I usually do in order to get the object I have selected, it was greyed out.  I just upgraded to Photoshop 2019 and have never had this problem previously.

Is there another way to save my selected work on a transparent background?  The decontaminate color box is how I was taught to get this result.