diff --git a/Category3D.gd b/Category3D.gd
index abc5b3d0..85fcb7d9 100644
--- a/Category3D.gd
+++ b/Category3D.gd
@@ -24,7 +24,7 @@ func clear_all():
 	for child in self.get_children():
 		child.queue_free()
 
-func remove_icon(icon_index):
+func remove_icon(icon_index: int):
 	var icon = self.icons[icon_index]
 	self.icons.remove(icon)
 	icon.queue_free()