added default mappable to None

fluents/plots.py

@@ -40,6 +40,7 @@ class Plot(view.View):
         # init matplotlib related stuff 
         self._background = None
         self._colorbar = None
+        self._mappable = None
         self._use_blit = False
         self.fig = Figure()
         self.canvas = FigureCanvasGTKAgg(self.fig)
@@ -136,11 +137,8 @@ class Plot(view.View):
 
     def _toggle_colorbar(self):
         if self._colorbar == None:
-            # get last created instance of mappable
-            if not self._mappable:
-                self._mappable = matplotlib.pylab.gci()
             if self._mappable == None:
-                print "No mappable"
+                logger.log('notice', 'No mappable in this plot')
                 return
             if self._mappable._A != None: # we need colormapping
                 # get axes original position