test if event.target is an element before calling closest(), fixes #5393

Closes #5393

Merge request studip/studip!4274

1 files changed, 4 insertions, 1 deletions

diff --git a/resources/assets/javascripts/studip-ui.js b/resources/assets/javascripts/studip-ui.js
index f563b31..ab2de3c 100644
--- a/resources/assets/javascripts/studip-ui.js
+++ b/resources/assets/javascripts/studip-ui.js
@@ -12,7 +12,10 @@ import RestrictedDatesHelper from './lib/RestrictedDatesHelper';
     $.widget( "ui.dialog", $.ui.dialog, {
         _allowInteraction: function( event ) {
             return hasParentWhich(isCKBodyWrapper)(event.target)
-                || event.target.closest('.studip-dialog') !== null
+                || (
+                    event.target instanceof Element
+                    && event.target.closest('.studip-dialog') !== null
+                )
                 || this._super( event );
         },
     });