Unfortunately it did NOT change to show it was shared in Windows 7 either. That has been a hot topic of discussion So it's kind of sad they didn't fix that. Knowing a folder is shared is super important. Knowing that you unshared a folder and are no longer allowing shared access (the locked icon) is not important since that is and should be the default assumed state of all folders unless they are shared (and why they should show the share icon).
The work around here may work for 8 though... (Use with caution, may break windows 8 since this is a windows 7 fix)