Add missing `isSelectable` option property in ShowOrderFormField

See #2973

diff --git a/wcfsetup/install/files/lib/system/form/builder/field/ShowOrderFormField.class.php b/wcfsetup/install/files/lib/system/form/builder/field/ShowOrderFormField.class.php
index 703212bcf140400d1b8763c503109edc0b671e26..ff782ffefde4aa857874ee94ee17c6cd9c193fed 100644 (file)
--- a/wcfsetup/install/files/lib/system/form/builder/field/ShowOrderFormField.class.php
+++ b/wcfsetup/install/files/lib/system/form/builder/field/ShowOrderFormField.class.php
@@ -77,6 +77,7 @@ class ShowOrderFormField extends SingleSelectionFormField {
                        array_unshift($this->nestedOptions, [
                                'depth' => 0,
                                'label' => WCF::getLanguage()->get('wcf.form.field.showOrder.firstPosition'),
+                               'isSelectable' => true,
                                'value' => 0
                        ]);