diff --git a/addons/web/static/src/legacy/js/core/dom.js b/addons/web/static/src/legacy/js/core/dom.js
index bfadd57bdd4..d1936859653 100644
--- a/addons/web/static/src/legacy/js/core/dom.js
+++ b/addons/web/static/src/legacy/js/core/dom.js
@@ -561,7 +561,9 @@ var dom = {
                 offsetTop = $el.offset().top;
                 el.classList.add('d-none');
             }
-            let elPosition = $scrollable[0].scrollTop + (offsetTop - $scrollable.offset().top);
+            const isDocScrollingEl = $scrollable.is(el.ownerDocument.scrollingElement);
+            let elPosition = offsetTop
+                - ($scrollable.offset().top - (isDocScrollingEl ? 0 : $scrollable[0].scrollTop));
             if (!isInOneDocument && $iframe.length) {
                 elPosition += $iframe.offset().top;
             }
diff --git a/addons/web/static/src/legacy/js/libs/jquery.js b/addons/web/static/src/legacy/js/libs/jquery.js
index 93404f98994..79ff64f298b 100644
--- a/addons/web/static/src/legacy/js/libs/jquery.js
+++ b/addons/web/static/src/legacy/js/libs/jquery.js
@@ -123,13 +123,21 @@ $.fn.extend({
         });
     },
     /**
+     * @todo Should really be converted to no jQuery and probably even removed
+     * from jQuery utilities in master
      * @return {jQuery}
      */
     closestScrollable() {
+        const document = this.length ? this[0].ownerDocument : window.document;
+
         let $el = this;
         while ($el[0] !== document.scrollingElement) {
-            // Avoid infinite loop.
-            if (!$el.length) {
+            if (!$el.length || $el[0] instanceof Document) {
+                // Ensure that $().closestScrollable() -> $() and handle the
+                // case of elements not attached to the DOM.
+                // Also, .parent() used to loop through ancestors can
+                // theoretically reach the document if nothing up to the HTML
+                // included is not scrollable.
                 return $();
             }
             if ($el.isScrollable()) {
@@ -173,9 +181,13 @@ $.fn.extend({
      * @returns {boolean}
      */
     isScrollable() {
+        if (!this.length) {
+            return false;
+        }
         const overflow = this.css('overflow-y');
+        const el = this[0];
         return overflow === 'auto' || overflow === 'scroll'
-            || (overflow === 'visible' && this === document.scrollingElement);
+            || (overflow === 'visible' && el === el.ownerDocument.scrollingElement);
     },
 });
 
diff --git a/addons/web_editor/static/src/js/editor/snippets.editor.js b/addons/web_editor/static/src/js/editor/snippets.editor.js
index b755bc9b014..8ffb992f94e 100644
--- a/addons/web_editor/static/src/js/editor/snippets.editor.js
+++ b/addons/web_editor/static/src/js/editor/snippets.editor.js
@@ -1693,6 +1693,9 @@ var SnippetsMenu = Widget.extend({
         if (!this.$scrollingElement[0]) {
             this.$scrollingElement = $(this.ownerDocument).find('.o_editable');
         }
+        this.$scrollingTarget = this.$scrollingElement.is(this.ownerDocument.scrollingElement)
+            ? $(this.ownerDocument.defaultView)
+            : this.$scrollingElement;
         this._onScrollingElementScroll = _.throttle(() => {
             for (const editor of this.snippetEditors) {
                 editor.toggleOverlayVisibility(false);
@@ -1710,7 +1713,7 @@ var SnippetsMenu = Widget.extend({
         // Setting capture to true allows to take advantage of event bubbling
         // for events that otherwise don’t support it. (e.g. useful when
         // scrolling a modal)
-        this.$scrollingElement[0].addEventListener('scroll', this._onScrollingElementScroll, {capture: true});
+        this.$scrollingTarget[0].addEventListener('scroll', this._onScrollingElementScroll, {capture: true});
 
         // Auto-selects text elements with a specific class and remove this
         // on text changes
@@ -1805,8 +1808,9 @@ var SnippetsMenu = Widget.extend({
             }
             this.$window.off('.snippets_menu');
             this.$document.off('.snippets_menu');
-            if (this.$scrollingElement) {
-                this.$scrollingElement[0].removeEventListener('scroll', this._onScrollingElementScroll, {capture: true});
+
+            if (this.$scrollingTarget) {
+                this.$scrollingTarget[0].removeEventListener('scroll', this._onScrollingElementScroll, {capture: true});
             }
         }
         core.bus.off('deactivate_snippet', this, this._onDeactivateSnippet);