There are some very usefull function like ResetOriginalValue() or SetModifiedFlag(), but nothing to reset modified status. When you save data and let the user continue (ie APPLY) you need something that reset all modified flags to FALSE. Without this function if you have an empty field and the user insert a string and save (looping on modified prop you write only new data) and then delete the string the status of prop returns to unmodified and when last save happen the prop is skipped (since not modified) and the data on disk is wrong.