diff --git a/sw/lib/ocaml/mapCanvas.ml b/sw/lib/ocaml/mapCanvas.ml
index 61a562440b..32dfc1f3f4 100644
--- a/sw/lib/ocaml/mapCanvas.ml
+++ b/sw/lib/ocaml/mapCanvas.ml
@@ -206,10 +206,10 @@ class widget = fun  ?(height=800) ?width ?wgs84_of_en () ->
     | _ -> false
 	  
 
-   method segment = fun ?(width=1) ?fill_color en1 en2 ->
+   method segment = fun ?(group = canvas#root) ?(width=1) ?fill_color en1 en2 ->
      let (x1, y1) = self#world_of_en en1
      and (x2, y2) = self#world_of_en en2 in
-     let l = GnoCanvas.line ?fill_color ~props:[`WIDTH_PIXELS width] ~points:[|x1;y1;x2;y2|] canvas#root in
+     let l = GnoCanvas.line ?fill_color ~props:[`WIDTH_PIXELS width] ~points:[|x1;y1;x2;y2|] group in
      l#show ();
      l
 end
diff --git a/sw/lib/ocaml/mapTrack.ml b/sw/lib/ocaml/mapTrack.ml
index b95456f930..e2a49dd710 100644
--- a/sw/lib/ocaml/mapTrack.ml
+++ b/sw/lib/ocaml/mapTrack.ml
@@ -38,7 +38,8 @@ class track = fun ?(name="coucou") ?(size = 50) ?(color="red") (geomap:MapCanvas
   let group = GnoCanvas.group geomap#canvas#root in
   let empty = ({ G.east = 0.; north = 0. },  GnoCanvas.line group) in
 
-  let aircraft = GnoCanvas.group group in
+  let aircraft = GnoCanvas.group group
+  and track = GnoCanvas.group group in
   let _ac_icon =
     ignore (GnoCanvas.line ~fill_color:color ~props:[`WIDTH_PIXELS 4;`CAP_STYLE `ROUND] ~points:[|0.;-6.;0.;14.|] aircraft);
     ignore (GnoCanvas.line ~fill_color:color ~props:[`WIDTH_PIXELS 4;`CAP_STYLE `ROUND] ~points:[|-9.;0.;9.;0.|] aircraft);
@@ -50,6 +51,8 @@ class track = fun ?(name="coucou") ?(size = 50) ?(color="red") (geomap:MapCanvas
     val mutable segments = Array.create size empty
     val mutable top = 0
     val mutable last = None
+    method track = track
+    method aircraft = aircraft
     method clear_one = fun i ->
       if segments.(i) != empty then begin
 	(snd segments.(i))#destroy ();
@@ -68,9 +71,9 @@ class track = fun ?(name="coucou") ?(size = 50) ?(color="red") (geomap:MapCanvas
       begin
 	match last with
 	  None -> 
-	    segments.(top) <- (en, geomap#segment ~fill_color:color en en)
+	    segments.(top) <- (en, geomap#segment ~group:track ~fill_color:color en en)
 	| Some last ->
-	    segments.(top) <- (en, geomap#segment ~width:2 ~fill_color:color last en)
+	    segments.(top) <- (en, geomap#segment ~group:track ~width:2 ~fill_color:color last en)
       end;
       self#incr;
       last <- Some en