what happened to my borders of stuff in the taskbar?

i'm not really sure when or how this happened, but it's kind of annoying. the borders on certain popup items in the taskbar just disappeared. i seem to remember having the same issue on either the beta or RC and it was easily fixed by a driver update, but that didn't do it this time. anyone else have this issue? and if you have, how did you fix it? i mean, it's really no big deal, but i'm kind of OCD about stuff matching lol. the attached picture can explain things a lot better than i can if what i said didn't help (the network and action center popups are missing the transparent border on the volume one).

Not sure but try - Check to see if the Visual Performance Options is set to Let Windows Choose or if the are set for Best Appearance. Right click My Computer - Advanced System Settings - Advanced - Settings - Visual Effect. Set for Best Appearance.