Merge branch '587-add-user-error' into 'devel_12.1.x'

Resolve "Add user error, PD map (Minerva 12.1.0, build 29/10/2018)"

See merge request !520

frontend-js/src/main/js/gui/admin/EditUserDialog.js

@@ -693,7 +693,10 @@ EditUserDialog.prototype.getSurname = function () {
  */
 EditUserDialog.prototype.close = function () {
   var self = this;
-  $(self.getElement()).dialog("close");
+  if ($(self.getElement()).hasClass("ui-dialog-content")) {
+    //close it only if it wasn't destroyed
+    $(self.getElement()).dialog("close");
+  }
 };
 
 /**