diff --git a/assets/libs/contao/contao-leaflet.js b/assets/libs/contao/contao-leaflet.js
index 33d1595..43b3f49 100644
--- a/assets/libs/contao/contao-leaflet.js
+++ b/assets/libs/contao/contao-leaflet.js
@@ -37,11 +37,13 @@ L.Contao = L.Class.extend({
             });
         });
 
-        // Set default pointToLayer and onEachFeature handler.
-        L.GeoJSON.AJAX.prototype.options = L.Util.extend({}, L.GeoJSON.AJAX.prototype.options, {
-            pointToLayer: this.pointToLayer.bind(this),
-            onEachFeature: this.onEachFeature.bind(this)
-        });
+        if (L.GeoJSON.AJAX) {
+            // Set default pointToLayer and onEachFeature handler.
+            L.GeoJSON.AJAX.prototype.options = {
+                pointToLayer: this.pointToLayer.bind(this),
+                onEachFeature: this.onEachFeature.bind(this)
+            };
+        }
     },
 
     /**
diff --git a/module/dca/tl_leaflet_layer.php b/module/dca/tl_leaflet_layer.php
index 7d76bea..8c3a028 100644
--- a/module/dca/tl_leaflet_layer.php
+++ b/module/dca/tl_leaflet_layer.php
@@ -5,8 +5,12 @@
 $GLOBALS['TL_DCA']['tl_leaflet_layer'] = array
 (
     'config' => array(
-        'dataContainer'    => 'Table',
-        'enableVersioning' => true,
+        'dataContainer'     => 'Table',
+        'enableVersioning'  => true,
+        'ctable'            => array('tl_leaflet_vector', 'tl_leaflet_marker'),
+        'ondelete_callback' => array(
+            array('Netzmacht\Contao\Leaflet\Dca\Layer', 'deleteRelations'),
+        ),
         'sql'              => array
         (
             'keys' => array
@@ -15,7 +19,7 @@ $GLOBALS['TL_DCA']['tl_leaflet_layer'] = array
                 'pid'   => 'index',
                 'alias' => 'unique',
             )
-        )
+        ),
     ),
     'list' => array
     (