diff --git a/frontend/src/utils/form/datepicker.js b/frontend/src/utils/form/datepicker.js
index c9cba1a8b..2c3ad9f61 100644
--- a/frontend/src/utils/form/datepicker.js
+++ b/frontend/src/utils/form/datepicker.js
@@ -185,7 +185,8 @@ export class Datepicker {
       const hasFocus                = event.relatedTarget !== null;
       const focussedIsNotTimepicker = !this.datepickerInstance.dt.contains(event.relatedTarget);
       const focussedIsNotElement    = event.relatedTarget !== this._element;
-      if (hasFocus && focussedIsNotTimepicker && focussedIsNotElement)
+      const focussedIsInDocument    = window.document.contains(event.relatedTarget);
+      if (hasFocus && focussedIsNotTimepicker && focussedIsNotElement && focussedIsInDocument)
         this.datepickerInstance.close();
     });