Index: theoryview/perspectives/theory/model_panel.py
===================================================================
--- theoryview/perspectives/theory/model_panel.py	(revision fb59ed90d8d3e021f0f291a9064098aae148158d)
+++ theoryview/perspectives/theory/model_panel.py	(revision d7b7156f5e3396b66f5f4b5c4a366e887b25df32)
@@ -168,20 +168,29 @@
                            wx.LEFT|wx.EXPAND|wx.ADJUST_MINSIZE, 15)
         ix += 1 
-        values = wx.StaticText(self, -1, 'Sigma (STD)')
-        values.SetToolTipString("Polydispersity multiplied by the value of the original parameter.")
-        self.sizer4_4.Add(values,( iy, ix),(1,1), wx.EXPAND|wx.ADJUST_MINSIZE, 0)
+        values = wx.StaticText(self, -1, 'Sigma [A]')
+        values.SetToolTipString(\
+        "Sigma(STD) in the A unit; the standard deviation from the mean value.")
+
+        self.sizer4_4.Add(values,( iy, ix),(1,1), wx.EXPAND|wx.ADJUST_MINSIZE, 
+                          0)
        
         ix += 1 
         npts = wx.StaticText(self, -1, 'Npts')
-        npts.SetToolTipString("Number of points for weighting.")
+        npts.SetToolTipString("Number of sampling points for the numerical\n\
+        integration over the distribution function.")
         self.sizer4_4.Add(npts,( iy, ix),(1,1), wx.EXPAND|wx.ADJUST_MINSIZE, 0)
         ix += 1 
         nsigmas = wx.StaticText(self, -1, 'Nsigmas')
-        nsigmas.SetToolTipString("Number of sigmas between which the range of the distribution function will be used for weighting. The value '3' covers 99.5% for Gaussian distribution function.")
-        self.sizer4_4.Add(nsigmas,( iy, ix),(1,1), wx.EXPAND|wx.ADJUST_MINSIZE, 0)
-        
+        nsigmas.SetToolTipString("   Number of sigmas between which the range\n\
+         of the distribution function will be used for weighting. \n\
+        The value '3' covers 99.5% for Gaussian distribution \n\
+        function.")
+        self.sizer4_4.Add(nsigmas,( iy, ix),(1,1), wx.EXPAND|wx.ADJUST_MINSIZE,
+                           0)
+         
         for item in self.model.dispersion.keys():
             if not item in self.model.orientation_params:
                 self.disp_cb_dict[item]= None
+                name0="Distribution of " + item
                 name1=item+".width"
                 name2=item+".npts"
@@ -191,5 +200,5 @@
                     if p=="width":
                         ix = 0
-                        name = wx.StaticText(self, -1,  name1)
+                        name = wx.StaticText(self, -1,  name0)
                         self.sizer4_4.Add( name,( iy, ix),(1,1),  
                                            wx.LEFT|wx.EXPAND|wx.ADJUST_MINSIZE, 15)
@@ -198,5 +207,7 @@
                         ctl1 = self.ModelTextCtrl(self, -1, size=(_BOX_WIDTH,20),
                                             style=wx.TE_PROCESS_ENTER)
-                        ctl1.SetToolTipString("Polydispersity multiplied by the value of the '%s'."%item)
+                        ctl1.SetToolTipString("Absolute Sigma: \n\
+                        1) It is the STD (ratio*mean) of '%s' distribution.\n \
+                        2) It should not exceed Mean/(2*Nsigmas)." %item)
                         ctl1.SetValue(str (format_number(value)))
                         self.sizer4_4.Add(ctl1, (iy,ix),(1,1), wx.EXPAND)
@@ -228,7 +239,9 @@
                             self.fixed_param.append([None,name3, Tctl2,
                                                      None,None, None, None,None])
+        first_orient  = True
         for item in self.model.dispersion.keys():
             if item in self.model.orientation_params:
                 self.disp_cb_dict[item]= None
+                name0="Distribution of " + item
                 name1=item+".width"
                 name2=item+".npts"
@@ -238,5 +251,5 @@
                     if p=="width":
                         ix = 0
-                        name = wx.StaticText(self, -1,  name1)
+                        name = wx.StaticText(self, -1,  name0)
                         self.sizer4_4.Add( name,( iy, ix),(1,1),  
                                            wx.LEFT|wx.EXPAND|wx.ADJUST_MINSIZE, 15)
@@ -249,5 +262,7 @@
                         ctl1 = self.ModelTextCtrl(self, -1, size=(_BOX_WIDTH,20),
                                             style=wx.TE_PROCESS_ENTER)
-                        ctl1.SetToolTipString("Polydispersity multiplied by the value of '%s'."%item)
+                        ctl1.SetToolTipString("Absolute Sigma: \n\
+                        1) It is the STD (ratio*mean) of '%s' distribution."% \
+                        item)
                         ctl1.SetValue(str (format_number(value)))
                         if not self.enable2D:
@@ -255,4 +270,11 @@
                             ctl1.Disable()
                         else:
+                            # in the case of 2D and angle parameter
+                            if first_orient:
+                                values.SetLabel('Sigma [A (or deg)]')
+                                values.SetToolTipString(\
+                                "Sigma(STD) in the A or deg(for angles) unit;\n\
+                                the standard deviation from the mean value.")
+                                first_orient = False 
                             ctl1.Show(True)
                             ctl1.Enable()
@@ -303,5 +325,5 @@
                             self.orientation_params_disp.append([None,name3, Tctl2,
                                                      None,None, None, None,None])
-            
+          
         msg = " Selected Distribution: Gaussian"        
         wx.PostEvent(self.parent, StatusEvent( status= msg )) 
