I often use the OSX application.   When I copy a field using the handy clipboard icon, it turns the field blue, and it stays that way.  If I copy it again (quite a common occurrence), it will turn a darker blue, making it impossible to read.  Copy yet again (not common) and it turns darker still.

I don't mind the blue coloring to show that I actually did copy the field, but it should return to normal text in a second, not stay that way.