fixes app build with kv usage/root widget + others typo

examples/RST_Editor/editor.kv

@@ -9,10 +9,10 @@ Root:
             size_hint_y: None
             height: 30
             Button:
-                text: 'load'
+                text: 'Load'
                 on_release: root.show_load()
             Button:
-                text: 'save'
+                text: 'Save'
                 on_release: root.show_save()
 
         BoxLayout:
@@ -36,11 +36,11 @@ Root:
             size_hint_y: None
             height: 30
             Button:
-                text: "cancel"
+                text: "Cancel"
                 on_release: root.cancel()
 
             Button:
-                text: "load"
+                text: "Load"
                 on_release: root.load(filechooser.path, filechooser.selection)
 
 <SaveDialog>:
@@ -63,10 +63,10 @@ Root:
             size_hint_y: None
             height: 30
             Button:
-                text: "cancel"
+                text: "Cancel"
                 on_release: root.cancel()
 
             Button:
-                text: "save"
+                text: "Save"
                 on_release: root.save(filechooser.path, text_input.text)
 

examples/RST_Editor/main.py

@@ -28,12 +28,12 @@ class Root(FloatLayout):
 
     def show_load(self):
         content = LoadDialog(load=self.load, cancel=self.dismiss_popup)
-        self._popup = Popup(title="load file", content=content, size_hint=(0.9, 0.9))
+        self._popup = Popup(title="Load file", content=content, size_hint=(0.9, 0.9))
         self._popup.open()
 
     def show_save(self):
         content = SaveDialog(save=self.save, cancel=self.dismiss_popup)
-        self._popup = Popup(title="save file", content=content, size_hint=(0.9, 0.9))
+        self._popup = Popup(title="Save file", content=content, size_hint=(0.9, 0.9))
         self._popup.open()
 
     def load(self, path, filename):

kivy/app.py

@@ -299,9 +299,11 @@ class App(EventDispatcher):
         If this method returns a widget (tree), it will be used as the root
         widget and added to the window.
 
-        :return: None or a root :class:`~kivy.uix.widget.Widget` instance
+        :return: None or a root :class:`~kivy.uix.widget.Widget` instance is no
+        self.root exist.
         '''
-        return Widget()
+        if not self.root:
+            return Widget()
 
     def build_config(self, config):
         '''.. versionadded:: 1.0.7

kivy/interactive.py

@@ -1,6 +1,6 @@
 '''
-InteractiveLauncher
-===================
+Interactive launcher
+====================
 
 .. versionadded:: 1.3.0