Delete files in host mac dropbox folder from parallels windows: still visible in finder.

Hi,
from Win7 64 on parallels, I can access folders on mac. I often add/remove files in mac dropbox shared folder.
Adding or deleting files in mac dropbox folder, often is not recognized by mac. You can still see deleted files in mac, also file info is given correctly. Trying to read, move or delete them triggers an error.
This created me more than one problem.
Any suggestion?