title: Kivy button (relative layout) no text on it
body: <p>So this is my noob code and problem - there is no text on buttons in . Why? If I add label text is still not displayed.
  In Carousel class text is added normally...
  Only one workaround I found is to add Label on top of button (but I don't like this idea)</p>
  
  <pre><code>from kivy.lang import Builder
  from kivy.uix.boxlayout import BoxLayout
  from kivy.uix.relativelayout import RelativeLayout
  from kivy.app import App
  from kivy.uix.carousel import Carousel
  
  Builder.load_string('''
  
  &lt;MainClass&gt;:
      BoxLayout:
          pos_hint: {"x": 0, "y": .85}
          Button:
              text: "saasas"
              on_press: root.next()
          Button:
              text: "saasas"
          Button:
              text: "PREV"
              on_press: root.prev()
  
  &lt;Carousel&gt;:
      size_hint: 1, .6
      BoxLayout:
          Button:
              text: "Asas"
          Button:
          Button:
      GridLayout:
          cols:2
          Button:
          Button:
          Button:
          Button:
  
  ''')
  
  class Add(BoxLayout):
      pass
  
  class MainClass(RelativeLayout):
      def __init__(self):
          RelativeLayout.__init__(self)
          self.car = Carousel()
          self.add_widget(self.car)
  
  
      def next(self, *args):
          print('next')
  
      def prev(self, *args):
          pass
  
  class Test(App):
      def build(self):
          return MainClass()
  Test().run()
  </code></pre>
  
  <p>I have no idea why this happen ...</p>
  
  <p>Here is actual look of this window:</p>
  
  <p><a href="https://i.stack.imgur.com/d6bg0.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/d6bg0.png" alt="enter image description here"></a></p>