diff -r d51af006fa6b -r 64d8f52bc8c8 dialogs/LDElementDialog.py
--- a/dialogs/LDElementDialog.py	Fri Aug 11 15:18:19 2017 +0300
+++ b/dialogs/LDElementDialog.py	Mon Aug 14 19:13:01 2017 +0300
@@ -41,7 +41,7 @@
 """
 
 class LDElementDialog(BlockPreviewDialog):
-    
+
     def __init__(self, parent, controller, tagname, type):
         """
         Constructor
@@ -50,24 +50,24 @@
         @param tagname: Tagname of project POU edited
         @param type: Type of LD element ('contact or 'coil')
         """
-        BlockPreviewDialog.__init__(self, parent, controller, tagname, 
+        BlockPreviewDialog.__init__(self, parent, controller, tagname,
               title=(_("Edit Contact Values")
                      if type == "contact"
                      else _("Edit Coil Values")))
-        
+
         # Init common sizers
-        self._init_sizers(2, 0, 
+        self._init_sizers(2, 0,
               (7 if type == "contact" else 9), None, 2, 1)
-        
+
         # Create label for LD element modifier
         modifier_label = wx.StaticText(self, label=_('Modifier:'))
-        self.LeftGridSizer.AddWindow(modifier_label, border=5, 
+        self.LeftGridSizer.AddWindow(modifier_label, border=5,
               flag=wx.GROW|wx.BOTTOM)
-        
+
         # Create radio buttons for selecting LD element modifier
         self.ModifierRadioButtons = {}
         first = True
-        element_modifiers = ([CONTACT_NORMAL, CONTACT_REVERSE, 
+        element_modifiers = ([CONTACT_NORMAL, CONTACT_REVERSE,
                               CONTACT_RISING, CONTACT_FALLING]
                              if type == "contact"
                              else [COIL_NORMAL, COIL_REVERSE, COIL_SET,
@@ -75,55 +75,55 @@
         modifiers_label = [_("Normal"), _("Negated")] + \
                           ([_("Set"), _("Reset")] if type == "coil" else []) + \
                           [_("Rising Edge"), _("Falling Edge")]
-        
+
         for modifier, label in zip(element_modifiers, modifiers_label):
-            radio_button = wx.RadioButton(self, label=label, 
+            radio_button = wx.RadioButton(self, label=label,
                   style=(wx.RB_GROUP if first else 0))
             radio_button.SetValue(first)
             self.Bind(wx.EVT_RADIOBUTTON, self.OnModifierChanged, radio_button)
             self.LeftGridSizer.AddWindow(radio_button, flag=wx.GROW)
             self.ModifierRadioButtons[modifier] = radio_button
             first = False
-        
+
         # Create label for LD element variable
         element_variable_label = wx.StaticText(self, label=_('Variable:'))
         self.LeftGridSizer.AddWindow(element_variable_label, border=5,
               flag=wx.GROW|wx.TOP)
-        
+
         # Create a combo box for defining LD element variable
         self.ElementVariable = wx.ComboBox(self, style=wx.CB_SORT)
-        self.Bind(wx.EVT_COMBOBOX, self.OnVariableChanged, 
+        self.Bind(wx.EVT_COMBOBOX, self.OnVariableChanged,
                   self.ElementVariable)
-        self.Bind(wx.EVT_TEXT, self.OnVariableChanged, 
-                  self.ElementVariable)        
+        self.Bind(wx.EVT_TEXT, self.OnVariableChanged,
+                  self.ElementVariable)
         self.LeftGridSizer.AddWindow(self.ElementVariable, border=5,
              flag=wx.GROW|wx.TOP)
-        
+
         # Add preview panel and associated label to sizers
         self.RightGridSizer.AddWindow(self.PreviewLabel, flag=wx.GROW)
         self.RightGridSizer.AddWindow(self.Preview, flag=wx.GROW)
-        
+
         # Add buttons sizer to sizers
-        self.MainSizer.AddSizer(self.ButtonSizer, border=20, 
+        self.MainSizer.AddSizer(self.ButtonSizer, border=20,
               flag=wx.ALIGN_RIGHT|wx.BOTTOM|wx.LEFT|wx.RIGHT)
-        
+
         # Save LD element class
         self.ElementClass = (LD_Contact if type == "contact" else LD_Coil)
-        
+
         # Extract list of variables defined in POU
         self.RefreshVariableList()
-        
+
         # Set values in ElementVariable
         for name, (var_type, value_type) in self.VariableList.iteritems():
             # Only select BOOL variable and avoid input for coil
             if (type == "contact" or var_type != "Input") and \
                value_type == "BOOL":
                 self.ElementVariable.Append(name)
-        
+
         self.Fit()
         # Normal radio button is default control having keyboard focus
         self.ModifierRadioButtons[element_modifiers[0]].SetFocus()
-    
+
     def GetElementModifier(self):
         """
         Return modifier selected for LD element
@@ -143,15 +143,15 @@
         """
         # For each parameters defined, set corresponding control value
         for name, value in values.items():
-            
+
             # Parameter is LD element variable
             if name == "variable":
                 self.ElementVariable.SetValue(value)
-            
+
             # Set value of other controls
             elif name == "modifier":
                 self.ModifierRadioButtons[value].SetValue(True)
-        
+
         # Refresh preview panel
         self.RefreshPreview()
 
@@ -188,20 +188,19 @@
         Override BlockPreviewDialog function
         """
         value = self.ElementVariable.GetValue()
-        
+
         # Set graphic element displayed, creating a LD element
         self.Element = self.ElementClass(
-                self.Preview, 
+                self.Preview,
                 self.GetElementModifier(),
                 value)
 
         button = self.ButtonSizer.GetAffirmativeButton()
         button.Enable(value != "")
-        
+
         # Call BlockPreviewDialog function
         BlockPreviewDialog.RefreshPreview(self)
-        
+
     def OnOK(self, event):
         if self.ElementVariable.GetValue() != "":
             self.EndModal(wx.ID_OK)
-