The "DataSet" attribute from Grids, the DataSetToolBar and DataSetControl goes missing fairly regularly. I do not know the circumstances that causes this to happen. The Edit component does not seem to have the same problem.
Similarly, the MouseLeave OnRowChanged, OnInitRow events are removed from their components regularly. The events have previously been defined as double-clinking on the events restores the events to the correct procedures.
I have seen a couple other posts that reported similar issues.