xcos Diagram does not show up after import

After importing it on Scilab's command line, a simple diagram (a constant block and a scope, attached) does not show any component on Xcos gui :

--> loadXcosLibs();
--> importXcosDiagram("constant.xcos");
--> scs_m

 scs_m = (diagram) with fields:

  props: (params tlist) with fields:
      wpar = [600,450,0,0,600,450]
      title: [2x1 string]
      tol: [1x7 double]
      tf = 30
      context = []
      void1 = []
      options: (scsopt tlist) with fields:
          3D: (2-elements list)
          Background = [8,1]
          Link = [1,5]
          ID: (2-elements list)
          Cmap = [0.8,0.8,0.8]
      void2 = []
      void3 = []
      doc: (empty list)
  objs: (5-elements list)
      (1): (CSCOPE Block)
      (2): (CONST Block)
      (3): (CLOCK_c Block)
  version = "scicos4.4"
  contrib: (empty list)

---> xcos(scs_m)
---> scicos_simulate(scs_m)

However, simulation runs fine.constant.zcos