HI

I work as a lab instructor, recently I got my students to use Zoho Docs for a spreadsheet exercise. They shared the spreadsheet with me so I could view and mark it, it is working fine except that for some of the sheets I can save the edited version but for others I cannot. I tried going to More Actions and Save As New Spreadsheet, but it appears that nothing has happened. Help with this would be greatly appreciated. 

Sheldon