I am on XP64, but I expect this may apply to vista too. LR 2.3
1) I save my adjusted raw file as a dng to the same folder as the original raw using the export function under the file menu.
2) I decide to do some more adjustment and export again using the same file name. I select overwright to update the existing dng with my new adjustments (I only want one dng file).
3) On inspection I find that the dng file is not updated. I have to sync the folder to get the new settings applied to the dng. Would be nice to have this done automatically.