Dislaying popup tip windows seems to work right now.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@15766 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

include/wx/gtk/popupwin.h

@@ -27,9 +27,7 @@ class wxPopupWindow: public wxPopupWindowBase
 {
 public:
     wxPopupWindow() { }
-#ifdef __DARWIN__
-    virtual ~wxPopupWindow() { }
-#endif
+    virtual ~wxPopupWindow();
 
     wxPopupWindow(wxWindow *parent, int flags = wxBORDER_NONE)
         { (void)Create(parent, flags); }