In my Data Sheet I have one record (row) which has a light green background. The rest of the rows have a white background as I would expect. There is nothing wrong with the data in the the record AFAICS.
I don’t understand what this means or why it occurs?
(That field will go away in a moment.)
In your menu, go to Field / Analyzye / Remove ALL Summaries
It appears that you have a Summary record which would have happened if you had accomplished a task such as Total (on a number field).
Many thanks, that explains the green line and also sorted out my date sorting issue. 