diff --git a/core/misc/dialog/off-canvas.es6.js b/core/misc/dialog/off-canvas.es6.js
index 5058b72d8d..df2c98e065 100644
--- a/core/misc/dialog/off-canvas.es6.js
+++ b/core/misc/dialog/off-canvas.es6.js
@@ -66,6 +66,9 @@
       // Clean up previous dialog event handlers.
       Drupal.offCanvas.removeOffCanvasEvents($element);
 
+      // Ensure the previous dialog, if any, is closed.
+      $('.ui-dialog-off-canvas .ui-dialog-titlebar-close').trigger('click');
+
       $('body').addClass('js-off-canvas-dialog-open');
       // @see http://api.jqueryui.com/position/
       settings.position = {
diff --git a/core/misc/dialog/off-canvas.js b/core/misc/dialog/off-canvas.js
index 1ac3158e9e..abd54a645a 100644
--- a/core/misc/dialog/off-canvas.js
+++ b/core/misc/dialog/off-canvas.js
@@ -25,6 +25,8 @@
 
       Drupal.offCanvas.removeOffCanvasEvents($element);
 
+      $('.ui-dialog-off-canvas .ui-dialog-titlebar-close').trigger('click');
+
       $('body').addClass('js-off-canvas-dialog-open');
 
       settings.position = {