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.