diff --git a/gerrit-gwtui/src/main/java/com/google/gerrit/client/diff/DiffTable.ui.xml b/gerrit-gwtui/src/main/java/com/google/gerrit/client/diff/DiffTable.ui.xml
index b757dd135d..98574845a1 100644
--- a/gerrit-gwtui/src/main/java/com/google/gerrit/client/diff/DiffTable.ui.xml
+++ b/gerrit-gwtui/src/main/java/com/google/gerrit/client/diff/DiffTable.ui.xml
@@ -97,6 +97,7 @@ limitations under the License.
     .difftable .CodeMirror.cm-keymap-fat-cursor div.CodeMirror-cursor {
       background: transparent;
       text-decoration: underline;
+      z-index: 2;
     }
     .showtabs .cm-tab:before {
       content: "\00bb";