Replaced function as button-attribute with lambda as button click handler.

system/workflow.py

@@ -145,8 +145,8 @@ class WorkflowView (gtk.VBox):
             # Add functions in each stage 
             for fun in stage.functions:
                 btn = gtk.Button(fun.name)
-                btn.connect('clicked', self.button_click_handler)
-                btn.function = fun
+                btn.connect('clicked',
+                            lambda button, f=fun : self.run_function(f))
 
                 btn_box.add(btn)
                 btn.show()
@@ -190,7 +190,4 @@ class WorkflowView (gtk.VBox):
             project.add_data(parent_data, new_data, function.name)
         
         logger.log('debug', 'Function ended: %s' % function.name)
-        
-    def button_click_handler(self, button):
-        self.run_function(function = button.function)