diff --git a/src/thumbnail.rs b/src/thumbnail.rs
index ea37bef..d304dba 100644
--- a/src/thumbnail.rs
+++ b/src/thumbnail.rs
@@ -18,7 +18,6 @@ mod imp {
     impl ObjectSubclass for Thumbnail {
         const NAME: &'static str = "Thumbnail";
         type Type = super::Thumbnail;
-        type ParentType = glib::Object;
         type Interfaces = (gdk::Paintable,);
     }