How do you stop editing a data grid cell

[Ray]

So a cell is open for editing in a data grid.  Click outside of the 
cell, it closes up (keeping the new data) and a 'closeFieldEditor' 
message is sent to the data grid group.  Good.

The problem is user don't always click outside the cell to manually 
close it up.  They may, for example, make a menu choice which opens a 
palette.  If they do, the new data in the cell is lost.  Sending 
'closeFieldEditor' does no good.

Ideas?