Numbers v5.1 missing rows unhide greyed out
I'm using Numbers V 5.1, and a multi-sheet workbook that I've been using for years, has on one of the sheets, the first 20 rows which will not display. Under Table, the 'Unhide Rows' option is greyed out. I read that someone said that filters might affect this option, but there are no filters on this sheet. Can anyone help?
iMac Pro