diff --git a/demo/index.html b/demo/index.html
index a656280..7df5333 100644
--- a/demo/index.html
+++ b/demo/index.html
@@ -123,7 +123,7 @@ <h1>MusicXML Player Demo</h1>
     <div>
       <label for="outputs">MIDI output</label>
       <select id="outputs"></select>
-      <input type="checkbox" class="renderer-option" id="option-mute" value="mute"/>
+      <input type="checkbox" class="player-option" id="option-mute" value="mute"/>
       <label for="option-mute">Mute</label>
       <div>
         If you're not using the local synth, you need to connect this output to a MIDI synth like FluidSynth, TiMidity, or <a href="https://mmontag.github.io/dx7-synth-js/" target="_blank">DX7 Synth</a>.