--- a/mobile/android/themes/core/aboutReaderControls.css
+++ b/mobile/android/themes/core/aboutReaderControls.css
@@ -119,16 +119,17 @@
   width: calc(100% - 30px);
   margin: 15px;
   z-index: 1000;
   background: #EBEBF0;
   visibility: hidden;
   border: 0;
   border-radius: 4px;
   box-shadow: 0px 4px 8px 0px rgba(0,0,0,0.40);
+  -moz-user-select: none;
 }
 
 /* Only used on desktop */
 .dropdown-popup > hr,
 .dropdown-arrow,
 #font-type-buttons > button > .name,
 #content-width-buttons,
 #line-height-buttons {