diff --git a/include/wx/popupwin.h b/include/wx/popupwin.h
index accdde8d5d..896e6f18f5 100644
--- a/include/wx/popupwin.h
+++ b/include/wx/popupwin.h
@@ -111,6 +111,8 @@ protected:
 
     friend class wxPopupWindowHandler;
     friend class wxPopupFocusHandler;
+
+    DECLARE_DYNAMIC_CLASS(wxPopupTransientWindow)
 };
 
 #if wxUSE_COMBOBOX && defined(__WXUNIVERSAL__)
@@ -138,6 +140,8 @@ protected:
 
     // the parent combobox
     wxComboControl *m_combo;
+
+    DECLARE_DYNAMIC_CLASS(wxPopupComboWindow)
 };
 
 #endif // wxUSE_COMBOBOX && defined(__WXUNIVERSAL__)
diff --git a/src/common/popupcmn.cpp b/src/common/popupcmn.cpp
index 55dcc2daa9..c78d74bcc4 100644
--- a/src/common/popupcmn.cpp
+++ b/src/common/popupcmn.cpp
@@ -46,6 +46,9 @@
     IMPLEMENT_DYNAMIC_CLASS(wxPopupWindow, wxWindow)
 #endif // __WXMSW__
 
+IMPLEMENT_DYNAMIC_CLASS(wxPopupTransientWindow, wxPopupWindow)
+IMPLEMENT_DYNAMIC_CLASS(wxPopupComboWindow, wxPopupTransientWindow)
+
 // ----------------------------------------------------------------------------
 // private classes
 // ----------------------------------------------------------------------------