diff --git a/demos/gtk-demo/markup.txt b/demos/gtk-demo/markup.txt
index e5e7ea67d0..79b857f295 100644
--- a/demos/gtk-demo/markup.txt
+++ b/demos/gtk-demo/markup.txt
@@ -5,7 +5,7 @@ Text <span color="gray">c<span color="green">o</span>l<span color="tomato">o</sp
 
 Colorful <span underline="low" underline-color="blue"><span underline="double" underline-color="red">under</span>lines</span> and <span background="pink"><span underline="error">mo</span><span underline="error" underline-color="green">re</span></span>
 
-Colorful <span strikethrough="true" strikethrough-color="magenta">strikethroughs</span>
+Colorful <span strikethrough="true" strikethrough-color="magenta">strikethroughs</span> and <span overline="single" overline_color="green">overlines</span>
 
 Superscripts and subscripts: 𝜀<span rise="-6000" size="x-small" font_desc="italic">0</span> = 𝜔<span rise="8000" size="smaller">𝜔<span rise="14000" size="smaller">𝜔<span rise="20000">.<span rise="23000">.<span rise="26000">.</span></span></span></span></span>