diff --git a/pylot/core/util/widgets.py b/pylot/core/util/widgets.py
index 6418fc71..7c3df3a5 100644
--- a/pylot/core/util/widgets.py
+++ b/pylot/core/util/widgets.py
@@ -9,6 +9,7 @@ import warnings
 import copy
 import datetime
 import numpy as np
+import math
 
 from matplotlib.figure import Figure
 from pylot.core.util.utils import find_horizontals
@@ -50,7 +51,7 @@ def getDataType(parent):
 
 def plot_pdf(_axes, x, y, annotation, bbox_props, xlabel=None, ylabel=None,
              title=None):
-    _axes.plot(x, y)
+    _axes.plot(x, y())
     if title:
         _axes.set_title(title)
     if xlabel:
@@ -242,54 +243,55 @@ class ComparisonDialog(QDialog):
                                          std=std, exp=exp)
         bbox_props = dict(boxstyle='round', facecolor='lightgrey', alpha=.7)
 
-        plot_pdf(_axes, x, y, annotation, bbox_props, 'time difference [s]',
-                 'propability density [-]', phase)
+        if math.isnan(std) == False:
+            plot_pdf(_axes, x, y, annotation, bbox_props, 'time difference [s]',
+                      'propability density [-]', phase)
 
-        pdf_a = copy.deepcopy(self.data.get('auto')[station][phase])
-        pdf_m = copy.deepcopy(self.data.get('manu')[station][phase])
+            pdf_a = copy.deepcopy(self.data.get('auto')[station][phase])
+            pdf_m = copy.deepcopy(self.data.get('manu')[station][phase])
 
-        xauto, yauto, stdauto, expauto, alim = pdf_a.axis, pdf_a.data, \
-                                               pdf_a.standard_deviation(), \
-                                               pdf_a.expectation(), \
-                                               pdf_a.limits()
-        xmanu, ymanu, stdmanu, expmanu, mlim = pdf_m.axis, pdf_m.data, \
-                                               pdf_m.standard_deviation(), \
-                                               pdf_m.expectation(), \
-                                               pdf_m.limits()
-        # find common limits
-        lims = clims(alim, mlim)
-        # relative x axis
-        x0 = lims[0]
-        xmanu -= x0
-        xauto -= x0
-        lims = [lim - x0 for lim in lims]
-        x0 = UTCDateTime(x0)
+            xauto, yauto, stdauto, expauto, alim = pdf_a.axis, pdf_a.data, \
+                                                   pdf_a.standard_deviation(), \
+                                                   pdf_a.expectation(), \
+                                                   pdf_a.limits()
+            xmanu, ymanu, stdmanu, expmanu, mlim = pdf_m.axis, pdf_m.data, \
+                                                   pdf_m.standard_deviation(), \
+                                                   pdf_m.expectation(), \
+                                                   pdf_m.limits()
+            # find common limits
+            lims = clims(alim, mlim)
+            # relative x axis
+            x0 = lims[0]
+            xmanu -= x0
+            xauto -= x0
+            lims = [lim - x0 for lim in lims]
+            x0 = UTCDateTime(x0)
 
-        # set annotation text
-        mannotation = "probability density for manual pick\n" \
-                      "expectation: {exp}\n" \
-                      "std: {std}".format(std=stdmanu,
-                                          exp=expmanu-x0.timestamp)
+            # set annotation text
+            mannotation = "probability density for manual pick\n" \
+                          "expectation: {exp}\n" \
+                          "std: {std}".format(std=stdmanu,
+                                              exp=expmanu-x0.timestamp)
 
-        aannotation = "probability density for automatic pick\n" \
-                      "expectation: {exp}\n" \
-                      "std: {std}".format(std=stdauto,
-                                          exp=expauto-x0.timestamp)
+            aannotation = "probability density for automatic pick\n" \
+                          "expectation: {exp}\n" \
+                          "std: {std}".format(std=stdauto,
+                                              exp=expauto-x0.timestamp)
 
-        _ax1 = plot_pdf(_ax1, xmanu, ymanu, mannotation,
-                        bbox_props=bbox_props, xlabel='seconds since '
-                                                      '{0}'.format(x0),
-                        ylabel='probability density [-]')
-        _ax1.set_xlim(lims)
+            _ax1 = plot_pdf(_ax1, xmanu, ymanu, mannotation,
+                            bbox_props=bbox_props, xlabel='seconds since '
+                                                          '{0}'.format(x0),
+                            ylabel='probability density [-]')
+            _ax1.set_xlim(lims)
 
-        _ax2 = plot_pdf(_ax2, xauto, yauto, aannotation,
-                        bbox_props=bbox_props, xlabel='seconds since '
+            _ax2 = plot_pdf(_ax2, xauto, yauto, aannotation,
+                            bbox_props=bbox_props, xlabel='seconds since '
                                                       '{0}'.format(x0))
-        _ax2.set_xlim(lims)
+            _ax2.set_xlim(lims)
 
-        _gs.update(wspace=0.5, hspace=0.5)
+            _gs.update(wspace=0.5, hspace=0.5)
 
-        self.canvas.draw()
+            self.canvas.draw()
 
     def plothist(self):
         name = self.sender().objectName()