diff --git a/samples/listctrl/listtest.cpp b/samples/listctrl/listtest.cpp
index dd01efe4f8..bfef9f62ab 100644
--- a/samples/listctrl/listtest.cpp
+++ b/samples/listctrl/listtest.cpp
@@ -724,7 +724,7 @@ void MyListCtrl::OnColClick(wxListEvent& event)
     int col = event.GetColumn();
 
     // set or unset image
-    static x = false;
+    static bool x = false;
     x = !x;
     SetColumnImage(col, x ? 0 : -1);