diff --git a/static/styles/zulip.css b/static/styles/zulip.css
index 998d076340..fc4e58661b 100644
--- a/static/styles/zulip.css
+++ b/static/styles/zulip.css
@@ -2465,6 +2465,9 @@ div.topic_edit_spinner .loading_indicator_spinner {
         width: 100%;
         min-width: 206px;
         box-sizing: border-box;
+        /* Setting resize as none hides the bottom right diagonal box
+           (which even has a background color of its own!). */
+        resize: none !important;
     }
 
     .control-group.no-margin {