diff --git a/kivy/core/text/markup.py b/kivy/core/text/markup.py
index 4d2e586a1..6cdf612f8 100644
--- a/kivy/core/text/markup.py
+++ b/kivy/core/text/markup.py
@@ -226,9 +226,10 @@ class MarkupLabel(MarkupLabelBase):
 
             # calculate the size of the part
             # (extract all extents of the part,
-            # sum the width, and get the maximum height)
+            # calculate width through extents due to kerning
+            # and get the maximum height)
             pg = [cache[g] for g in part]
-            pw = sum([g[0] for g in pg])
+            pw = get_extents(part)[0]
             ph = max([g[1] for g in pg])
 
             options = copy(options)
diff --git a/kivy/data/style.kv b/kivy/data/style.kv
index 74d8b2184..4b527e21c 100644
--- a/kivy/data/style.kv
+++ b/kivy/data/style.kv
@@ -93,7 +93,7 @@
     padding_y: 6
     canvas.before:
         Color:
-            rgb: self.background_color
+            rgba: self.background_color
         BorderImage:
             border: (16, 16, 16, 16)
             pos: self.pos
@@ -105,7 +105,7 @@
             pos: map(int, self.cursor_pos)
             size: 1, -self.line_height
         Color:
-            rgb: self.foreground_color
+            rgba: self.foreground_color
 
 <TextInputCutCopyPaste>:
     size_hint: None, None