UI: Update UI and resources.

src/myApp/ui/resources.qrc

 <RCC>
   <qresource prefix="icons">
+    <file>refresh.png</file>
+    <file>auto-refresh.png</file>
     <file>export.png</file>
     <file>exit.png</file>
     <file>load_lattice.png</file>

src/myApp/ui/ui_app.py

@@ -43,7 +43,7 @@ class Ui_MainWindow(object):
         self.elem_name_cbb = QtWidgets.QComboBox(self.centralwidget)
         sizePolicy = QtWidgets.QSizePolicy(QtWidgets.QSizePolicy.Preferred,
                                            QtWidgets.QSizePolicy.Fixed)
-        sizePolicy.setHorizontalStretch(1)
+        sizePolicy.setHorizontalStretch(0)
         sizePolicy.setVerticalStretch(0)
         sizePolicy.setHeightForWidth(
             self.elem_name_cbb.sizePolicy().hasHeightForWidth())
@@ -423,6 +423,19 @@ class Ui_MainWindow(object):
                         QtGui.QIcon.Normal, QtGui.QIcon.Off)
         self.actionExport_Lattice.setIcon(icon4)
         self.actionExport_Lattice.setObjectName("actionExport_Lattice")
+        self.actionUpdate = QtWidgets.QAction(MainWindow)
+        icon5 = QtGui.QIcon()
+        icon5.addPixmap(QtGui.QPixmap(":/icons/refresh.png"),
+                        QtGui.QIcon.Normal, QtGui.QIcon.Off)
+        self.actionUpdate.setIcon(icon5)
+        self.actionUpdate.setObjectName("actionUpdate")
+        self.actionAuto_Update = QtWidgets.QAction(MainWindow)
+        self.actionAuto_Update.setCheckable(True)
+        icon6 = QtGui.QIcon()
+        icon6.addPixmap(QtGui.QPixmap(":/icons/auto-refresh.png"),
+                        QtGui.QIcon.Normal, QtGui.QIcon.Off)
+        self.actionAuto_Update.setIcon(icon6)
+        self.actionAuto_Update.setObjectName("actionAuto_Update")
         self.menu_Help.addAction(self.actionContents)
         self.menu_Help.addSeparator()
         self.menu_Help.addAction(self.action_About)
@@ -431,6 +444,8 @@ class Ui_MainWindow(object):
         self.menubar.addAction(self.menu_Help.menuAction())
         self.toolBar.addAction(self.actionLoad_Lattice)
         self.toolBar.addAction(self.actionExport_Lattice)
+        self.toolBar.addAction(self.actionUpdate)
+        self.toolBar.addAction(self.actionAuto_Update)
         self.toolBar.addAction(self.actionE_xit)
 
         self.retranslateUi(MainWindow)
@@ -460,6 +475,9 @@ class Ui_MainWindow(object):
             self.trajectory_layout_plot.setXLimitMin)
         self.actionLoad_Lattice.triggered.connect(MainWindow.onLoadLattice)
         self.actionExport_Lattice.triggered.connect(MainWindow.onExportLatfile)
+        self.actionAuto_Update.toggled['bool'].connect(
+            MainWindow.onAutoUpdateModel)
+        self.actionUpdate.triggered.connect(MainWindow.onUpdateModel)
         QtCore.QMetaObject.connectSlotsByName(MainWindow)
 
     def retranslateUi(self, MainWindow):
@@ -539,6 +557,8 @@ class Ui_MainWindow(object):
         self.actionExport_Lattice.setToolTip(
             _translate("MainWindow",
                        "Export physics model to a FLAME lattice file."))
+        self.actionUpdate.setText(_translate("MainWindow", "Update"))
+        self.actionAuto_Update.setText(_translate("MainWindow", "Auto Update"))
 
 
 from mpl4qt.widgets.mplbasewidget import MatplotlibBaseWidget

src/myApp/ui/ui_app.ui

@@ -54,7 +54,7 @@
        <widget class="QComboBox" name="elem_name_cbb">
         <property name="sizePolicy">
          <sizepolicy hsizetype="Preferred" vsizetype="Fixed">
-          <horstretch>1</horstretch>
+          <horstretch>0</horstretch>
           <verstretch>0</verstretch>
          </sizepolicy>
         </property>
@@ -712,6 +712,8 @@
    </attribute>
    <addaction name="actionLoad_Lattice"/>
    <addaction name="actionExport_Lattice"/>
+   <addaction name="actionUpdate"/>
+   <addaction name="actionAuto_Update"/>
    <addaction name="actionE_xit"/>
   </widget>
   <action name="action_About">
@@ -774,6 +776,27 @@
     <string>Export physics model to a FLAME lattice file.</string>
    </property>
   </action>
+  <action name="actionUpdate">
+   <property name="icon">
+    <iconset resource="resources.qrc">
+     <normaloff>:/icons/refresh.png</normaloff>:/icons/refresh.png</iconset>
+   </property>
+   <property name="text">
+    <string>Update</string>
+   </property>
+  </action>
+  <action name="actionAuto_Update">
+   <property name="checkable">
+    <bool>true</bool>
+   </property>
+   <property name="icon">
+    <iconset resource="resources.qrc">
+     <normaloff>:/icons/auto-refresh.png</normaloff>:/icons/auto-refresh.png</iconset>
+   </property>
+   <property name="text">
+    <string>Auto Update</string>
+   </property>
+  </action>
  </widget>
  <customwidgets>
   <customwidget>
@@ -1047,6 +1070,38 @@
     </hint>
    </hints>
   </connection>
+  <connection>
+   <sender>actionAuto_Update</sender>
+   <signal>toggled(bool)</signal>
+   <receiver>MainWindow</receiver>
+   <slot>onAutoUpdateModel()</slot>
+   <hints>
+    <hint type="sourcelabel">
+     <x>-1</x>
+     <y>-1</y>
+    </hint>
+    <hint type="destinationlabel">
+     <x>866</x>
+     <y>456</y>
+    </hint>
+   </hints>
+  </connection>
+  <connection>
+   <sender>actionUpdate</sender>
+   <signal>triggered()</signal>
+   <receiver>MainWindow</receiver>
+   <slot>onUpdateModel()</slot>
+   <hints>
+    <hint type="sourcelabel">
+     <x>-1</x>
+     <y>-1</y>
+    </hint>
+    <hint type="destinationlabel">
+     <x>866</x>
+     <y>456</y>
+    </hint>
+   </hints>
+  </connection>
  </connections>
  <slots>
   <slot>onAbout()</slot>
@@ -1056,5 +1111,7 @@
   <slot>on_ellipse_size_changed()</slot>
   <slot>onLoadLattice()</slot>
   <slot>onExportLatfile()</slot>
+  <slot>onUpdateModel()</slot>
+  <slot>onAutoUpdateModel()</slot>
  </slots>
 </ui>