Version 5.0.0 beta 8

applications/cms/sources/Blocks/Block.php

@@ -40,11 +40,14 @@ use IPS\Patterns\ActiveRecord;
 use IPS\Request;
 use IPS\Theme;
 use IPS\Widget;
+use IPS\Widget\Polymorphic;
 use LogicException;
 use OutOfRangeException;
 use ParseError;
+use function class_implements;
 use function defined;
 use function func_get_args;
+use function get_class;
 use function in_array;
 use function intval;
 use function is_array;
@@ -628,9 +631,17 @@ EOF;
 		{
 			$templates = array( '_default_' => Member::loggedIn()->language()->addToStack('content_block_template_use_default') );
 
+			$keys =[ $this->widget()->key ];
+			if( in_array( Polymorphic::class, class_implements( $this->widget() ) ) )
+			{
+				/* @var Polymorphic $widgetClass */
+				$widgetClass = get_class( $this->widget() );
+				$keys[] = $widgetClass::getBaseKey();
+			}
+
 			foreach( Templates::getTemplates( Templates::RETURN_BLOCK ) as $id => $obj )
 			{
-				if ( $obj->group == $this->widget()->key )
+				if( in_array( $obj->group, $keys ) )
 				{
 					$templates[ $obj->key ] = $obj->title;
 				}