You can add event code that will reclac on selection change. There is no
event generated when a cell is coloured so selection change is about as close
as you will get. This will force a recalc of all dirty cells each time the
cursor is moved. By adding application.volatile to the original code you get
very close to what you were looking for...

'**In a standard code module
Public Function ComputeCount(ByVal Cell As Range) As Integer
Application.Volatile
If Cell.Interior.Color = vbRed Then
'* do the math one way
ComputeCount = 1
Else
'* do the math another way
ComputeCount = 2
End If
End Function

'** In the Thisworkbook module
Private Sub Workbook_SheetSelectionChange(ByVal Sh As Object, ByVal Target
As Range)
Sh.Calculate
End Sub
--
HTH...

Jim Thomlinson


"Mark VII" wrote:

Jim --

It is important to note that changing the colour of a cell does not trigger
a calculation, nor does it dirty the cell to force a recalculation of the
cells pointing at it...<

That's an interesting point. Is there a way to detect that the cursor has
left a particular cell, or is there a way to capture the cell that was last
edited? Under my set of somewhat arcane circumstances, I can work around the
lack of automatic recalculation when cell color changes if I can monitor a
given area of the worksheet for edits. My thought is that if I can detect
that a particular cell was edited, I can force a calculation in the dependent
area of my workbook.

Thanks,
Mark