\label{Spreadsheet_Cell_Editing}

To edit a cell in the spreadsheet, move you mouse pointer over it until you 
are able to follow a link.  Click on the link to open up an editing window.  
The current contents of the cell will be shown and can be modified.  
Pressing the ``Accept'' button will cause the spreadsheet to be updated with 
the new formula.  
You will then be working with an unsaved modified copy of a spreadsheet.  
See \textbf{Spreadsheet Files} \ref{Spreadsheet_Files} for information on 
loading and saving spreadsheets.
Pressing the ``Discard Changes'' button will discard any changes you have
made to the contents of the cell.

\textbf{What goes in a cell}

The cells of the spreadsheet contain a mixture of Perl commands and LON-CAPA
specific functions (\ref{Spreadsheet_Functions}).  
Most non-IO Perl functions work in cells.