>It is the cell that focus is on that doesn't update
>IOW the field under the cursor doens't update,
>all other modified cells do update.

So it's not a grid problem :) Wouldn't update if it was a plain textbox control on form too.
Toolbar click doesn't cause a control to loose focus, IOW you're still in that cell.
A quick and dirty solution (Assuming al default grid controls):

if type('_Screen.ActiveForm.Activecontrol') = 'O' ;
 and !isnull(_Screen.ActiveForm.Activecontrol) ;
 and _Screen.ActiveForm.Activecontrol.BaseClass = 'Grid'
 With _Screen.ActiveForm.Activecontrol
 	With .Columns(.ActiveColumn).Controls(2)
 	 .Value = .Value
 	endwith
 endwith
 tableupdate(2,.f.,_Screen.ActiveForm.Activecontrol.Recordsource)
endif

Cetin