diff --git a/demos/calc.cpp b/demos/calc.cpp
index 6556aa5..d8b7aa0 100644
--- a/demos/calc.cpp
+++ b/demos/calc.cpp
@@ -27,6 +27,7 @@ struct Calculator {
     for(auto& [name, cell] : $gui.cells()) {
       auto id = $gui.entity(name);
       $gui.set<guecs::Rectangle>(id, {});
+      $gui.set<guecs::Effect>(id, {});
       $gui.set<guecs::Label>(id, {guecs::to_wstring(name)});
       $gui.set<guecs::Clickable>(id, {
           [=](auto, auto) { fmt::println("clicked {}", name); }