diff --git a/debug-viewer/GstDebugViewer/Plugins/Timeline.py b/debug-viewer/GstDebugViewer/Plugins/Timeline.py
index 25df69b751..9e9ab4976e 100644
--- a/debug-viewer/GstDebugViewer/Plugins/Timeline.py
+++ b/debug-viewer/GstDebugViewer/Plugins/Timeline.py
@@ -414,6 +414,7 @@ class TimelineWidget (gtk.DrawingArea):
             self.__redraw ()
 
         gc = gtk.gdk.GC (self.window)
+        # FIXME: Accept a subregion here to speed up partial expose.
         self.window.draw_drawable (gc, self.__offscreen, 0, 0, 0, 0, -1, -1)
         self.__draw_position (self.window)