I know it has been a while since this was posted, but I had the same problem
as you were describing (WS_Calculate is occurring even when a change is made
on another WS that should not trigger the event) and after searching I found
the following response from Jim Thomlinson which helped me out greatly. As
Jim describes, I had "volatile" functions on the sheet with the WS_Change
event and these volatile functions would calculate anytime a change was made
on the sheet or on any other sheet. Try an experiment similar to the one
Dave Peterson mentioned in this post and you will see that a =Now() or
=Today() function will calculate when any change on any sheet is made.
Hopefully it is helpful to someone else with the same problem.

Copied message as follows (from 8/30/2005)...

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=Now() is a volatile function, meaning that it calculates every time that a
calculation is executed. If you can, try to find a way to replace the now
function with a constant. You can update the constant base on some other
event such as a sheet activate or workbook open or... Otherwise you can also
add a criteria to the calculation event that ThisWorkbook is the active
workbook. If it isn't then abort the rest of the procedure.
--
HTH...

Jim Thomlinson


"Alex" wrote:

I'm usinin the following code to highlight the filtered column with a
different collar.
To make it works I've entered =Now() in some cell.
Everything is fine. But, when I'm opening another spreadsheet the procedure
is being automatically triggered producing the error "out of range".

Private Sub Worksheet_Calculate()
Dim af As AutoFilter
Dim fFilter As Filter
Dim iFilterCount As Integer
'Application.EnableEvents = False
If Worksheets("Initiatives").AutoFilterMode Then ' gettin an error "out of
range"
Set af = Worksheets("Initiatives").AutoFilter
iFilterCount = 1
Worksheets("Initiatives").Unprotect ("donit")
For Each fFilter In af.Filters
If fFilter.On Then
af.Range.Cells(1, iFilterCount) _
.Interior.ColorIndex = 3 ' 15 - gray; 35 - mint green
Else
af.Range.Cells(1, iFilterCount) _
.Interior.ColorIndex = 15
End If
iFilterCount = iFilterCount + 1
Next fFilter

Else
Worksheets("Initiatives").Range("A1").AutoFilter
Worksheets("Initiatives").Range("A1:H1").Interior. ColorIndex = 15
End If

How could I fix it?

Thanks