diff --git a/src/sao.less b/src/sao.less
index f959a4a553..c5458ebb2d 100644
--- a/src/sao.less
+++ b/src/sao.less
@@ -344,6 +344,7 @@ img.icon {
             background-color: @body-bg;
             position: sticky;
             top: 0;
+            z-index: 100;
         }
         > tbody > tr > td {
             cursor: pointer;