In that case, I think you are going to have to evaluate each character:
Code:
Sub ScratchMacro()
'A basic Word macro coded by Greg Maxey
Dim oChrRange As Range
For Each oChrRange In ActiveDocument.Characters
If Not oChrRange.Font.Shading.BackgroundPatternColor = wdColorAutomatic Then
oChrRange.Font.Shading.BackgroundPatternColor = wdColorAutomatic
oChrRange.HighlightColorIndex = wdBrightGreen
End If
Next oChrRange
lbl_Exit:
Exit Sub
End Sub