diff --git a/src/msw/dialog.cpp b/src/msw/dialog.cpp
index bda7218983..eb1db5599b 100644
--- a/src/msw/dialog.cpp
+++ b/src/msw/dialog.cpp
@@ -211,7 +211,7 @@ wxDialog::~wxDialog()
 
 bool wxDialog::IsModal() const
 {
-    return !wxModelessWindows.Member(this);
+    return !wxModelessWindows.Find(this);
 }
 
 bool wxDialog::IsModalShowing() const