=== modified file 'data/gtkbuilder/main.ui'
--- data/gtkbuilder/main.ui	2014-02-10 15:10:12 +0000
+++ data/gtkbuilder/main.ui	2016-02-19 10:27:13 +0000
@@ -1052,6 +1052,69 @@
                 <property name="tab_fill">False</property>
               </packing>
             </child>
+            <child>
+              <object class="GtkBox" id="dev_options">
+                <property name="visible">True</property>
+                <property name="can_focus">False</property>
+                <property name="border_width">12</property>
+                <property name="orientation">vertical</property>
+                <property name="spacing">6</property>
+                <child>
+                  <object class="GtkFrame" id="frame_children1">
+                    <property name="visible">True</property>
+                    <property name="can_focus">False</property>
+                    <property name="label_xalign">0</property>
+                    <property name="shadow_type">none</property>
+                    <child>
+                      <object class="GtkAlignment" id="alignment1">
+                        <property name="visible">True</property>
+                        <property name="can_focus">False</property>
+                        <property name="top_padding">6</property>
+                        <property name="left_padding">12</property>
+                        <child>
+                          <object class="GtkBox" id="dev_box">
+                            <property name="visible">True</property>
+                            <property name="can_focus">False</property>
+                            <property name="orientation">vertical</property>
+                            <child>
+                              <placeholder/>
+                            </child>
+                          </object>
+                        </child>
+                      </object>
+                    </child>
+                    <child type="label">
+                      <object class="GtkLabel" id="label_updates1">
+                        <property name="visible">True</property>
+                        <property name="can_focus">False</property>
+                        <property name="label" translatable="yes">Proposed updates are only for testing updates and providing development feedback. Enabling this may introduce instability.</property>
+                        <property name="use_markup">True</property>
+                        <property name="wrap">True</property>
+                      </object>
+                    </child>
+                  </object>
+                  <packing>
+                    <property name="expand">False</property>
+                    <property name="fill">True</property>
+                    <property name="position">0</property>
+                  </packing>
+                </child>
+              </object>
+              <packing>
+                <property name="position">5</property>
+              </packing>
+            </child>
+            <child type="tab">
+              <object class="GtkLabel" id="label7">
+                <property name="visible">True</property>
+                <property name="can_focus">False</property>
+                <property name="label" translatable="yes">Developer Options</property>
+              </object>
+              <packing>
+                <property name="position">5</property>
+                <property name="tab_fill">False</property>
+              </packing>
+            </child>
           </object>
           <packing>
             <property name="expand">True</property>

=== modified file 'softwareproperties/gtk/SoftwarePropertiesGtk.py'
--- softwareproperties/gtk/SoftwarePropertiesGtk.py	2015-11-01 12:39:02 +0000
+++ softwareproperties/gtk/SoftwarePropertiesGtk.py	2016-02-19 10:27:13 +0000
@@ -328,6 +328,8 @@
         # Setup the checkbuttons for the child repos / updates
         for checkbutton in self.vbox_updates.get_children():
             self.vbox_updates.remove(checkbutton)
+        for checkbutton in self.dev_box.get_children():
+            self.dev_box.remove(checkbutton)
         if len(self.distro.source_template.children) < 1:
             self.frame_children.hide()
         for template in self.distro.source_template.children:
@@ -341,7 +343,10 @@
             self.handlers[checkbox] = checkbox.connect("toggled",
                                                    self.on_checkbutton_child_toggled,
                                                    template)
-            self.vbox_updates.add(checkbox)
+            if "proposed" in template.name:
+                self.dev_box.add(checkbox)
+            else:
+                self.vbox_updates.add(checkbox)
             checkbox.show()
 
         # setup the server chooser
@@ -376,6 +381,12 @@
             checkbox.set_active(active)
             checkbox.set_inconsistent(inconsistent)
 
+        # Enable or disable the child source checkbuttons
+        for checkbox in self.dev_box.get_children():
+            (active, inconsistent) = self.get_comp_child_state(checkbox.template)
+            checkbox.set_active(active)
+            checkbox.set_inconsistent(inconsistent)
+
         # Enable or disable the component checkbuttons
         for checkbox in self.vbox_dist_comps.get_children():
             # check if the comp is enabled
@@ -387,9 +398,11 @@
         # and source code
         if len(self.distro.enabled_comps) < 1:
             self.vbox_updates.set_sensitive(False)
+            self.dev_box.set_sensitive(False)
             self.checkbutton_source_code.set_sensitive(False)
         else:
             self.vbox_updates.set_sensitive(True)
+            self.dev_box.set_sensitive(True)
             self.checkbutton_source_code.set_sensitive(True)
 
         # Check for source code sources