diff --git a/include/preferences.html b/include/preferences.html
index 7a68546..bea1624 100644
--- a/include/preferences.html
+++ b/include/preferences.html
@@ -860,6 +860,18 @@
     </ul>
   </li>
 </ul>      
+
+<h3 id="preferences-midi-port-config">Modifiers</h3>
+
+<p>
+  This page allows to set options for input and output MIDI devices, such as:
+</p>
+
+<ul>
+  <li><kbd class="menu">Music data</kbd>: whether Ardour should accept/send note events from/to selected MIDI device</li>
+  <li><kbd class="menu">Control data</kbd>: whether Ardour should accept/send control events (Control Change, or CC) from/to selected MIDI device</li>
+  <li><kbd class="menu">Follow selection</kbd>: whether Ardour should connect this device to a selected track only (only applicable to input devices)</li>
+</ul>
   
 <h2 id="preferences-transport">Transport</h2>