When a coauthored document has a cell with a colored outline around it, what is it suggesting?

Question

(1 point)
Spellcheck has detected an error.
The cell is hidden from others’ view.
Someone else is working on that cell.
The cell is protected from alterations.

Answer 1

When a coauthored document has a cell with a colored outline around it, it is suggesting that someone else is working on that cell.