Well you didn't ask for it, but<g> ...
Goes in a standard/regular module:
'--
Public FormulaCount As Long
Sub ResetInteriorAndFontColors()
Dim rCell As Range
For Each rCell In Application.Intersect(Selection, ActiveSheet.UsedRange).Cells
If rCell.Interior.Color = vbBlue Then
rCell.Interior.ColorIndex = xlColorIndexNone
rCell.Font.ColorIndex = xlColorIndexAutomatic
End If
Next
End Sub
'--
Goes in the "ThisWorkbook" module:
'--
Private Sub Workbook_Open()
FormulaCount = ThisWorkbook.Worksheets("Sheet1").Cells.SpecialCells(xlCellTypeFormulas).Count
End Sub
'--
Goes in the worksheet module of the sheet with the formulas:
'--
Private Sub Worksheet_Change(ByVal Target As Range)
On Error GoTo BadChange
Application.EnableEvents = False
If FormulaCount > Me.Cells.SpecialCells(xlCellTypeFormulas).Count Then
Target.Interior.Color = vbBlue
Target.Font.Color = vbYellow
End If
FormulaCount = Me.Cells.SpecialCells(xlCellTypeFormulas).Count
BadChange:
Application.EnableEvents = True
End Sub
'--
Note: Change all references to "Sheet1" to the actual sheet name.
--
Jim Cone