diff --git a/less/mixins.less b/less/mixins.less
index 733dfd08b4..6eaffa3e31 100644
--- a/less/mixins.less
+++ b/less/mixins.less
@@ -15,6 +15,9 @@
   &:after {
     display: table;
     content: "";
+    // Fixes Opera/contenteditable bug:
+    // http://nicolasgallagher.com/micro-clearfix-hack/#comment-36952
+    line-height: 0;
   }
   &:after {
     clear: both;