DocumentViewer: Trigger GC on done

Controls.DocumentViewer/DocumentViewer.vb

@@ -69,8 +69,14 @@ Public Class DocumentViewer
     ''' Terminate Viewer, freeing up resources and deleting temp files
     ''' </summary>
     Public Sub Done()
+        _logger.Debug("Done: Deleting Temp Files")
         DeleteTempFiles()
+
+        _logger.Debug("Done: Closing Documents")
         FreeFile()
+
+        _logger.Debug("Done: Triggering GC")
+        GC.Collect()
     End Sub
 
     ''' <summary>
@@ -150,7 +156,7 @@ Public Class DocumentViewer
 
     Private Sub FreeFile()
         Try
-            If Len(_FilePath) OrElse _Fileinfo Is Nothing Then
+            If Len(_FilePath) = 0 OrElse _Fileinfo Is Nothing Then
                 Exit Sub
             End If
             Dim oExtension As String = _Fileinfo.Extension.ToUpper