diff --git a/src/core/meta-cursor-tracker.c b/src/core/meta-cursor-tracker.c
index cdf389f82..7480ed698 100644
--- a/src/core/meta-cursor-tracker.c
+++ b/src/core/meta-cursor-tracker.c
@@ -949,6 +949,7 @@ meta_cursor_tracker_queue_redraw (MetaCursorTracker *tracker)
 
   g_assert (meta_is_wayland_compositor ());
 
+  /* Clear the location the cursor was at before, if we need to. */
   if (tracker->previous_is_valid)
     {
       clip.x = tracker->previous_rect.x;