Paste disabled

I have narrowed it down to the following bit of code!

 Private Sub Worksheet_SelectionChange(ByVal Target As Range)

For Each cell In Range("F5:F1000")
If cell > "" Then
cell.EntireRow.Interior.ColorIndex = 6  
Else
cell.EntireRow.Interior.ColorIndex = xlNone
End If

Next cell

End Sub

If (cell.EntireRow.Interior.ColorIndex = 6) and ('cell.EntireRow.Interior.ColorIndex = xlNone) are removed, then Paste works!

Can anyone tell me what is going on and how to fix it?

Here iis an example
sample4.zip