diff --git a/public/assets/js/bridge/blocks-custom.js b/public/assets/js/bridge/blocks-custom.js
index b9622e5..56e89ba 100644
--- a/public/assets/js/bridge/blocks-custom.js
+++ b/public/assets/js/bridge/blocks-custom.js
@@ -96,50 +96,54 @@
         const BaseModel = baseType.model || editor.DomComponents.Component;
         const BaseView = baseType.view || editor.DomComponents.View;
 
-        const PlaceholderModel = BaseModel.extend({
-            defaults: {
-                name: 'Placeholder',
-                tagName: 'span',
-                droppable: false,
-                attributes: {
-                    'data-placeholder-type': 'custom',
-                    'data-placeholder-key': 'UEBERSCHRIFT',
-                },
-                traits: [
-                    {
-                        type: 'select',
-                        name: 'data-placeholder-type',
-                        label: 'Typ',
-                        options: [
-                            { id: 'custom', label: 'Allgemein' },
-                            { id: 'database', label: 'Datenbank' },
-                        ],
-                        changeProp: true,
-                    },
-                    {
-                        type: 'text',
-                        name: 'data-placeholder-key',
-                        label: 'Bezeichner',
-                        placeholder: 'UEBERSCHRIFT',
-                        changeProp: true,
-                    },
-                    {
-                        type: 'select',
-                        name: 'data-placeholder-table',
-                        label: 'Tabelle',
-                        options: [],
-                        changeProp: true,
-                    },
-                    {
-                        type: 'select',
-                        name: 'data-placeholder-column',
-                        label: 'Feld',
-                        options: [],
-                        changeProp: true,
-                    },
+        const placeholderDefaults = {};
+        if (BaseModel.prototype && BaseModel.prototype.defaults) {
+            for (const key in BaseModel.prototype.defaults) {
+                placeholderDefaults[key] = BaseModel.prototype.defaults[key];
+            }
+        }
+        placeholderDefaults.name = 'Placeholder';
+        placeholderDefaults.tagName = 'span';
+        placeholderDefaults.droppable = false;
+        placeholderDefaults.attributes = {
+            'data-placeholder-type': 'custom',
+            'data-placeholder-key': 'UEBERSCHRIFT',
+        };
+        placeholderDefaults.traits = [
+            {
+                type: 'select',
+                name: 'data-placeholder-type',
+                label: 'Typ',
+                options: [
+                    { id: 'custom', label: 'Allgemein' },
+                    { id: 'database', label: 'Datenbank' },
                 ],
+                changeProp: true,
             },
+            {
+                type: 'text',
+                name: 'data-placeholder-key',
+                label: 'Bezeichner',
+                placeholder: 'UEBERSCHRIFT',
+                changeProp: true,
+            },
+            {
+                type: 'select',
+                name: 'data-placeholder-table',
+                label: 'Tabelle',
+                options: [],
+                changeProp: true,
+            },
+            {
+                type: 'select',
+                name: 'data-placeholder-column',
+                label: 'Feld',
+                options: [],
+                changeProp: true,
+            },
+        ];
 
+        const PlaceholderModel = BaseModel.extend({
             init() {
                 this.listenTo(this, 'change:attributes', this.updatePlaceholderState);
                 this.updatePlaceholderState();
@@ -229,6 +233,8 @@
             }
         });
 
+        PlaceholderModel.prototype.defaults = placeholderDefaults;
+
         PlaceholderModel.isComponent = function (el) {
             if (el && el.hasAttribute && el.hasAttribute('data-placeholder-type')) {
                 return { type: PLACEHOLDER_COMPONENT };