Experiments: Deal with new scan data more robustly.

dstat_interface/core/experiments/experiment_template.py

@@ -514,11 +514,19 @@ class PlotBox(object):
         line_number -- line number to update
         """
         for subplot in Experiment.data:
-            self.subplots[subplot].lines[line_number].set_xdata(
-                Experiment.data[subplot][line_number][0])
-            self.subplots[subplot].lines[line_number].set_ydata(
-                Experiment.data[subplot][line_number][1])
-                
+            while True:
+                try:
+                    self.subplots[subplot].lines[line_number].set_xdata(
+                        Experiment.data[subplot][line_number][0])
+                    self.subplots[subplot].lines[line_number].set_ydata(
+                        Experiment.data[subplot][line_number][1])
+                except IndexError:
+                    self.addline()
+                except KeyError:
+                    pass
+                else:
+                    break
+                    # logger.warning("Tried to set line %s that doesn't exist.", line_number)
     def changetype(self, Experiment):
         """Change plot type. Set axis labels and x bounds to those stored
         in the Experiment instance. Stores class instance in Experiment.