title: Kivy: setting the color of text on a disabled button in kv
body: <p>I'm trying to set the color of the text on a disabled button separate from the normal color of the button text. As buttons are based on Label i tried to change disabled_color but with out success.
  As you can see in the image the font color of the disabled button (left) is still the same as the normal button right. <a href="https://i.stack.imgur.com/DiZ2K.png" rel="nofollow noreferrer">Disabled (left) and normal (right) botton</a> Please help me set the text color correct.
  I`m using python 3.7.3 and kivy 1.10.1</p>
  
  <pre><code>Button:
      #Set font
      font_size: '35sp'
      color: 1,1,1,1
      disabled_color: 25.0/255.0,25.0/255.0,25.0/255.0,1
      #Set background
      background_normal: 'button_normal.png'
      background_down: 'button_down.png'
      background_disabled_normal: 'button_normal_disn.png'
      background_disabled_down: 'button_normal_disd.png'
  </code></pre>