Change the Attachment icon color.
Late last year one of the other MS Outlook ‘improvements’ was that you changed some of the column icon colors within Outlook. The bad is that you changed the file attachment 'paper clip' icon to a darker gray. So if you have a Black theme set as I do, the difference between the background and the icon are so slim, you can’t really see it. Either give uses control of colors, or make the attachment icon a more obvious color for the black theme.