+<h4>Mouse wheel</h4>
+<p>
+ Some GUI elements can optionally be controlled with the mouse wheel when
+ the pointer is hovering over them. The notation for mouse wheel action is
+ <kbd class="mouse">⇑</kbd> <kbd class="mouse">⇐</kbd></dt>
+ <kbd class="mouse">⇓</kbd> <kbd class="mouse">⇒</kbd></dt>
+</p>
+