Don't override Zend's Checkbox for our toggle switch

library/Icinga/Web/Form/Element/Checkbox.php

@@ -0,0 +1,43 @@
+<?php
+/* Icinga Web 2 | (c) 2019 Icinga Development Team | GPLv2+ */
+
+namespace Icinga\Web\Form\Element;
+
+class Checkbox extends \Zend_Form_Element_Checkbox
+{
+    public function loadDefaultDecorators()
+    {
+        parent::loadDefaultDecorators();
+
+        if (! $this->loadDefaultDecoratorsIsDisabled()) {
+            $class = 'toggle-switch';
+            if ($this->getAttrib('disabled')) {
+                $class .= ' disabled';
+            }
+            $currentDecorators = $this->getDecorators();
+            $pos = array_search('Zend_Form_Decorator_ViewHelper', array_keys($currentDecorators), true);
+            $decorators = array_slice($currentDecorators, 0, $pos);
+            $decorators += [
+                'ToggleSwitchOpen' => [
+                    ['ToggleSwitchOpen' => 'HtmlTag'],
+                    ['tag' => 'label', 'class' => $class, 'openOnly' => true, 'placement' => 'append']
+                ]
+            ];
+            $decorators += array_slice($currentDecorators, $pos, 1);
+            $decorators += [
+                'ToggleSlider'      => [
+                    ['ToggleSlider' => 'HtmlTag'],
+                    ['tag' => 'span', 'class' => 'toggle-slider', 'placement' => 'append']
+                ],
+                'ToggleSwitchClose' => [
+                    ['ToggleSwitchClose' => 'HtmlTag'],
+                    ['tag' => 'label', 'closeOnly' => true, 'placement' => 'append']
+                ]
+            ];
+            $decorators += array_slice($currentDecorators, $pos + 1);
+            $this->setDecorators($decorators);
+        }
+
+        return $this;
+    }
+}

library/vendor/Zend/View/Helper/FormCheckbox.php

@@ -76,10 +76,8 @@ class Zend_View_Helper_FormCheckbox extends Zend_View_Helper_FormElement
 
         // is the element disabled?
         $disabled = '';
-        $classDisabled = '';
         if ($disable) {
             $disabled = ' disabled="disabled"';
-            $classDisabled = ' disabled';
         }
 
         // build the element
@@ -94,17 +92,14 @@ class Zend_View_Helper_FormCheckbox extends Zend_View_Helper_FormElement
             unset($attribs['disableHidden']);
         }
 
-        $xhtml .= '<label class="toggle-switch' . $classDisabled .'">'
+        $xhtml .= '<input type="checkbox"'
-                . '<input type="checkbox"'
                 . ' name="' . $this->view->escape($name) . '"'
                 . ' id="' . $this->view->escape($id) . '"'
                 . ' value="' . $this->view->escape($checkedOptions['checkedValue']) . '"'
                 . $checkedOptions['checkedString']
                 . $disabled
                 . $this->_htmlAttribs($attribs)
-                . $this->getClosingBracket()
+                . $this->getClosingBracket();
-                . '<span class="toggle-slider"></span>'
-                . '</label>';
 
         return $xhtml;
     }