Mac & Photoshop: Screen capture of an application then pasting it into a new document in photoshop issue

Mac & Photoshop: Screen capture of an application then pasting it into a new document in photoshop issue

This used to work perfectly up until about a month or two ago. When doing a screen capture onto the clipboard (cmd + ctr + shift + 4) and pasting it into a new document in Photoshop (only in photoshop, pasting it elsewhere like mail works fine), the drop shadow around the application doesn't look right. What can i do to fix this?