change mouse scroll behaviour

Controls.DocumentViewer/DocumentViewer.vb

@@ -116,7 +116,7 @@ Public Class DocumentViewer
             Dim oFileInfo = New IO.FileInfo(FilePath)
             Dim oExtension As String = oFileInfo.Extension.ToUpper
 
-            Select Case oExtension
+            Select Case oExtension.ToUpper
                 Case ".MSG"
                     Dim oMsg As New Independentsoft.Msg.Message(FilePath)
                     ' TODO: Improve Encoding, maybe convert based on encoding