diff --git a/source b/source
index afb055f3c00..6a20902700c 100644
--- a/source
+++ b/source
@@ -63281,8 +63281,8 @@ fur
      button</span>, then set <var>result</var> to <var>submitter</var>'s <span
      data-x="concept-fe-optional-value">optional value</span>.</p></li>
 
-     <li><p><span>Close the dialog</span> <var>subject</var> with <var>result</var> and
-     null.</p></li>
+     <li><p><span>Close the dialog</span> <var>subject</var> with <var>result</var>, null, and
+     false.</p></li>
 
      <li><p>Return.</p></li>
     </ol>
@@ -65126,26 +65126,20 @@ interface <dfn interface>HTMLDialogElement</dfn> : <span>HTMLElement</span> {
 
   </div>
 
-  <div class="note" id="note-dialog-remove-open-attribute">
-   <p>Removing the <code data-x="attr-dialog-open">open</code> attribute will usually hide the
-   dialog. However, doing so has a number of strange additional consequences:
-
-   <ul>
-    <li><p>The <code data-x="event-close">close</code> event will not be fired.</p></li>
+  <div algorithm>
+  <p>The following <span data-x="concept-element-attributes-change-ext">attribute change
+  steps</span>, given <var>element</var>, <var>localName</var>, <var>oldValue</var>,
+  <var>value</var>, and <var>namespace</var> are used for <code>dialog</code> elements:</p>
 
-    <li><p>The <code data-x="dom-dialog-close">close()</code> method, and any <span data-x="close
-    request">close requests</span>, will no longer be able to close the dialog.</p></li>
+  <ol>
+   <li><p>If <var>namespace</var> is not null, then return.</p></li>
 
-    <li><p>If the dialog was shown using its <code data-x="dom-dialog-showModal">showModal()</code>
-    method, the <code>Document</code> will still be <span data-x="blocked by a modal
-    dialog">blocked</span>.</p></li>
-   </ul>
+   <li><p>If <var>localName</var> is not <code data-x="attr-dialog-open">open</code>, then
+   return.</p></li>
 
-   <p>For these reasons, it is generally better to never remove the <code
-   data-x="attr-dialog-open">open</code> attribute manually. Instead, use the <code
-   data-x="dom-dialog-requestclose">requestClose()</code> or <code
-   data-x="dom-dialog-close">close()</code> methods to close the dialog, or the <code
-   data-x="attr-hidden">hidden</code> attribute to hide it.</p>
+   <li><p>If <var>value</var> is null, then <span>close the dialog</span> given
+   <var>element</var>, null, null, and true.</p></li>
+  </ol>
   </div>
 
   <p>The <code data-x="attr-tabindex">tabindex</code> attribute must not be specified on
@@ -65266,8 +65260,8 @@ interface <dfn interface>HTMLDialogElement</dfn> : <span>HTMLElement</span> {
   <ol>
    <li><p>If <var>returnValue</var> is not given, then set it to null.</p></li>
 
-   <li><p><span>Close the dialog</span> <span>this</span> with <var>returnValue</var> and
-   null.</p></li>
+   <li><p><span>Close the dialog</span> <span>this</span> with <var>returnValue</var>, null, and
+   false.</p></li>
   </ol>
   </div>
 
@@ -65293,11 +65287,7 @@ interface <dfn interface>HTMLDialogElement</dfn> : <span>HTMLElement</span> {
     <li><p>Hiding a dialog is different from closing one. Closing a dialog gives it a return value,
     fires an event, unblocks the page for other dialogs, and so on. Whereas hiding a dialog is a
     purely visual property, and is something you can already do with the <code
-    data-x="attr-hidden">hidden</code> attribute or by removing the <code
-    data-x="attr-dialog-open">open</code> attribute. (See also the <a
-    href="#note-dialog-remove-open-attribute">note above</a> about removing the <code
-    data-x="attr-dialog-open">open</code> attribute, and how hiding the dialog in that way is
-    generally not desired.)</p></li>
+    data-x="attr-hidden">hidden</code> attribute.</p></li>
 
     <li><p>Showing a dialog is different from opening one. Opening a dialog consists of creating
     and showing that dialog (similar to how <code data-x="dom-open">window.open()</code> both
@@ -65547,7 +65537,7 @@ interface <dfn interface>HTMLDialogElement</dfn> : <span>HTMLElement</span> {
 
      <li><p><i data-x="create-close-watcher-closeAction">closeAction</i> being to <span>close the
      dialog</span> given <var>dialog</var>, <var>dialog</var>'s <span>request close return
-     value</span>, and <var>dialog</var>'s <span>request close source element</span>.</p></li>
+     value</span>, <var>dialog</var>'s <span>request close source element</span>, and false.</p></li>
 
      <li><p><i data-x="create-close-watcher-getEnabledState">getEnabledState</i> being to return
      true if <var>dialog</var>'s <span>enable close watcher for request close</span> is true or
@@ -65585,14 +65575,14 @@ interface <dfn interface>HTMLDialogElement</dfn> : <span>HTMLElement</span> {
    data-x="attr-button-command-close-state">Close</span> state and <var>element</var> has an <code
    data-x="attr-dialog-open">open</code> attribute, then <span>close the dialog</span>
    <var>element</var> with <var>source</var>'s <span data-x="concept-fe-optional-value">optional
-   value</span> and <var>source</var>.</p></li>
+   value</span> and <var>source</var>, and false.</p></li>
 
    <li><p>If <var>command</var> is in the <span
    data-x="attr-button-command-request-close-state">Request Close</span> state and
    <var>element</var> has an <code data-x="attr-dialog-open">open</code> attribute, then <span
    data-x="dialog-request-close">request to close the dialog</span> <var>element</var> with
-   <var>source</var>'s <span data-x="concept-fe-optional-value">optional value</span> and
-   <var>source</var>.</p></li>
+   <var>source</var>'s <span data-x="concept-fe-optional-value">optional value</span>,
+   <var>source</var>, and false.</p></li>
 
    <li><p>If <var>command</var> is the <span
    data-x="attr-button-command-show-modal-state">Show Modal</span> state and <var>element</var> does
@@ -65626,12 +65616,12 @@ interface <dfn interface>HTMLDialogElement</dfn> : <span>HTMLElement</span> {
 
   <div algorithm>
   <p>When a <code>dialog</code> element <var>subject</var> is to be <dfn data-x="close the
-  dialog">closed</dfn>, with null or a string <var>result</var> and an <code>Element</code> or null
-  <var>source</var>, run these steps:</p>
+  dialog">closed</dfn>, with null or a string <var>result</var>, an <code>Element</code> or null
+  <var>source</var>, and a boolean <var>removingOpenAttribute</var>, run these steps:</p>
 
   <ol>
    <li><p>If <var>subject</var> does not have an <code data-x="attr-dialog-open">open</code>
-   attribute, then return.</p></li>
+   attribute and <var>removingOpenAttribute</var> is false, then return.</p></li>
 
    <li><p><span data-x="concept-event-fire">Fire an event</span> named <code
    data-x="event-beforetoggle">beforetoggle</code>, using <code>ToggleEvent</code>, with the <code
@@ -65642,13 +65632,13 @@ interface <dfn interface>HTMLDialogElement</dfn> : <span>HTMLElement</span> {
    <var>subject</var>.</p></li>
 
    <li><p>If <var>subject</var> does not have an <code data-x="attr-dialog-open">open</code>
-   attribute, then return.</p></li>
+   attribute, and <var>removingOpenAttribute</var> is false, then return.</p></li>
 
    <li><p><span>Queue a dialog toggle event task</span> given <var>subject</var>, "<code
    data-x="">open</code>", "<code data-x="">closed</code>", and <var>source</var>.</p></li>
 
-   <li><p>Remove <var>subject</var>'s <code data-x="attr-dialog-open">open</code>
-   attribute.</p></li>
+   <li><p>If <var>removingOpenAttribute</var> is false, then remove <var>subject</var>'s <code
+   data-x="attr-dialog-open">open</code> attribute.</p></li>
 
    <li><p>If <span>is modal</span> of <var>subject</var> is true, then <span>request an
    element to be removed from the top layer</span> given <var>subject</var>.</p></li>
@@ -65666,7 +65656,8 @@ interface <dfn interface>HTMLDialogElement</dfn> : <span>HTMLElement</span> {
    <li><p>Set <var>subject</var>'s <span>request close source element</span> to null.</p></li>
 
    <li>
-    <p>If <var>subject</var>'s <span>previously focused element</span> is not null, then:</p>
+    <p>If <var>subject</var>'s <span>previously focused element</span> is not null and
+    <var>removingOpenAttribute</var> is false, then:</p>
 
     <ol>
      <li><p>Let <var>element</var> be <var>subject</var>'s <span>previously focused