diff --git a/core/modules/startup/browser-messaging.js b/core/modules/startup/browser-messaging.js
index e5068cfcc2..1ed2760929 100644
--- a/core/modules/startup/browser-messaging.js
+++ b/core/modules/startup/browser-messaging.js
@@ -60,7 +60,7 @@ Unload library iframe for given url
 */
 function unloadIFrame(url){
 	var iframes = document.getElementsByTagName("iframe");
-	for(var t=iframes.length-1; t--; t>=0) {
+	for(var t = iframes.length - 1; t >= 0; t--) {
 		var iframe = iframes[t];
 		if(iframe.getAttribute("library") === "true" &&
 		  iframe.getAttribute("src") === url) {
diff --git a/editions/tw5.com/tiddlers/releasenotes/5.5.0/#10018-fix-unload-iframe-leak.tid b/editions/tw5.com/tiddlers/releasenotes/5.5.0/#10018-fix-unload-iframe-leak.tid
new file mode 100644
index 0000000000..5bd3787e09
--- /dev/null
+++ b/editions/tw5.com/tiddlers/releasenotes/5.5.0/#10018-fix-unload-iframe-leak.tid
@@ -0,0 +1,12 @@
+change-category: internal
+change-type: bugfix
+created: 20260907175854854
+description: Fixed a DOM leak when closing the plugin library
+github-links: https://github.com/TiddlyWiki/TiddlyWiki5/pull/10018
+release: 5.5.0
+tags: $:/tags/ChangeNote
+title: $:/changenotes/5.5.0/#10018
+type: text/vnd.tiddlywiki
+github-contributors: DesignThinkerer
+
+Fixed a syntax error in the `unloadIFrame` loop that permanently left a hidden `<iframe library="true">` attached to the DOM every time the plugin library modal was closed.
\ No newline at end of file