diff --git a/src/main/frontend/extensions/pdf/core.cljs b/src/main/frontend/extensions/pdf/core.cljs
index eb562ade5f..58be7503b0 100644
--- a/src/main/frontend/extensions/pdf/core.cljs
+++ b/src/main/frontend/extensions/pdf/core.cljs
@@ -688,15 +688,15 @@
        (when-let [grouped-hls (and (sequential? highlights) (group-by :page highlights))]
          (doseq [page loaded-pages]
            (when-let [^js/HTMLDivElement hls-layer (pdf-utils/resolve-hls-layer! viewer page)]
-             (let [page-hls (get grouped-hls page)]
-
-               (rum/mount
-                (pdf-highlights-region-container
-                 viewer page-hls {:show-ctx-menu! show-ctx-menu!
-                                  :upd-hl!        upd-hl!})
-
-                hls-layer)))))
-
+             (let [page-hls (get grouped-hls page)
+                   hls-render (pdf-highlights-region-container
+                                   viewer page-hls {:show-ctx-menu! show-ctx-menu!
+                                                    :upd-hl! upd-hl!})
+                   ^js mounted-root (.-mountedRoot hls-layer)]
+               (if (nil? mounted-root)
+                 (->> (rum/mount hls-render hls-layer)
+                   (set! (. hls-layer -mountedRoot)))
+                 (.render mounted-root hls-render))))))
        ;; destroy
        #())
      [loaded-pages highlights])