diff --git a/doc/theme3/specification.md b/doc/theme3/specification.md
index b3c6c382..6189898d 100644
--- a/doc/theme3/specification.md
+++ b/doc/theme3/specification.md
@@ -443,6 +443,8 @@ The following properties are currently supports:
       Margin on the outside of the widget.
     * border:          border
       Border around the widget (between padding and margin)/
+    * border-radius:    padding
+      Sets a radius on the corners of the borders.
     * background:      color
       Background color.
     * foreground:      color