The filters on my spreasheet are in the 3rd row, and show the filtering dropdown.
When I click on the filter downdrop arrow to select some information, only an empty cell appears as the choice.
I also noticed that the dropdown arrow symbol appears to be duplicated, like one behind another.
Interestingly enough, when I create a copy of the spreadsheet (right click on the tab name ► select "Move or Copy" ► check the "Select a copy" box ► In the "Move selected sheets to Book:" dropdown, I select ""(new book)".
When the new workbook is created, it does not have the issue described above.
I have looked through the web and tried the miriad of suggestiona for various days to no avail.
I'd appreciate your help.