diff --git a/themes/tiddlywiki/stickytitles/styles.tid b/themes/tiddlywiki/stickytitles/styles.tid
index 179a7084d..43c442ea8 100644
--- a/themes/tiddlywiki/stickytitles/styles.tid
+++ b/themes/tiddlywiki/stickytitles/styles.tid
@@ -11,4 +11,5 @@ tags: [[$:/tags/Stylesheet]]
   position: sticky;
   top: 0px;
   background: <<colour tiddler-background>>;
+  z-index: 500;
 }