SumByColor with cell click

I have code that changes a cell fill to yellow when clicked... and back to blank when clicked again. This works fine.

Private Sub Worksheet_BeforeDoubleClick(ByVal Target As Range, Cancel As Boolean)
    Cancel = True
    Target.Interior.ColorIndex = IIf(Target.Interior.ColorIndex >= 6, -4142, 6)
End Sub

I'm using a UDF to sum cells by color with this, and this too works fine.

Function SumByColor(CellColor As Range, rRange As Range)
Dim cSum As Long
Dim ColIndex As Integer
ColIndex = CellColor.Interior.ColorIndex
For Each cl In rRange
  If cl.Interior.ColorIndex = ColIndex Then
    cSum = WorksheetFunction.SUM(cl, cSum)
  End If
Next cl
SumByColor = cSum
End Function

Finally, I'm using

=SumByColor(J1,F3:F5)

and this works... but I want it to work at each cell click within F3:F5.

How do I make this formula fire when clicking in cell F3:F5? Seems like it should do it but I can't make it work. The only way it will work is if I click in the cell with the formula and hit enter.

I believe I need a selection change event. Am I correct?

Thanks for all you guys much smarter at this than I am. See attached picture.

Excel1.png