diff --git a/doc/en/Gdk/Drawable.xml b/doc/en/Gdk/Drawable.xml
index 50e88053a..3092f077a 100644
--- a/doc/en/Gdk/Drawable.xml
+++ b/doc/en/Gdk/Drawable.xml
@@ -587,9 +587,10 @@ You must call the Destroy method on the returned region when done.
         <Parameter Name="angle2" Type="System.Int32" />
       </Parameters>
       <Docs>
-        <summary>Draws an arc or a filled 'pie slice'.</summary>
+        <summary>Draws an arc or a filled 'pie slice'. The arc is defined by the bounding rectangle of the entire ellipse, and the start and end angles of the part of the ellipse to be drawn.</summary>
         <param name="gc">a <see cref="T:Gdk.GC" /></param>
-        <param name="filled">a <see cref="T:System.Boolean" /></param>
+        <param name="filled">
+          <i>true</i> if the arc should be filled, producing a 'pie slice'.</param>
         <param name="x">The x-coordinate of the upper left hand of the bounding box of the arc.
 </param>
         <param name="y">The y-coordinate of the upper left hand of the bounding box of the arc.
@@ -1160,4 +1161,4 @@ The clip mask of gc is ignored, but clip rectangles and clip regions work fine.
       </Docs>
     </Member>
   </Members>
-</Type>
+</Type>
\ No newline at end of file