diff --git a/framework/core/js/forum/src/utils/affixSidebar.js b/framework/core/js/forum/src/utils/affixSidebar.js
index 0acacbb5f..6d062d7b0 100644
--- a/framework/core/js/forum/src/utils/affixSidebar.js
+++ b/framework/core/js/forum/src/utils/affixSidebar.js
@@ -4,22 +4,38 @@
  *
  * @param {DOMElement} element
  * @param {Boolean} isInitialized
+ * @param {Object} context
  */
-export default function affixSidebar(element, isInitialized) {
+export default function affixSidebar(element, isInitialized, context) {
   if (isInitialized) return;
 
-  const $sidebar = $(element);
-  const $header = $('#header');
-  const $footer = $('#footer');
+  const onresize = () => {
+    const $sidebar = $(element);
+    const $header = $('#header');
+    const $footer = $('#footer');
+    const $affixElement = $sidebar.find('> ul');
 
-  // Don't affix the sidebar if it is taller than the viewport (otherwise
-  // there would be no way to scroll through its content).
-  if ($sidebar.outerHeight(true) > $(window).height() - $header.outerHeight(true)) return;
+    $(window).off('.affix');
+    $affixElement
+      .removeClass('affix affix-top affix-bottom')
+      .removeData('bs.affix');
 
-  $sidebar.find('> ul').affix({
-    offset: {
-      top: () => $sidebar.offset().top - $header.outerHeight(true) - parseInt($sidebar.css('margin-top'), 10),
-      bottom: () => this.bottom = $footer.outerHeight(true)
-    }
-  });
+    // Don't affix the sidebar if it is taller than the viewport (otherwise
+    // there would be no way to scroll through its content).
+    if ($sidebar.outerHeight(true) > $(window).height() - $header.outerHeight(true)) return;
+
+    $affixElement.affix({
+      offset: {
+        top: () => $sidebar.offset().top - $header.outerHeight(true) - parseInt($sidebar.css('margin-top'), 10),
+        bottom: () => this.bottom = $footer.outerHeight(true)
+      }
+    });
+  };
+
+  // Register the affix plugin to execute on every window resize (and trigger)
+  $(window).on('resize', onresize).resize();
+
+  context.onunload = () => {
+    $(window).off('resize', onresize);
+  }
 }