use update UI handler for the up and new directory buttons instead of manually updating the controls, this fixes a bug where up button wasn't enabled back after selecting a child of top level directory

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@48794 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

include/wx/generic/filedlgg.h

@@ -83,13 +83,14 @@ public:
     void OnNew( wxCommandEvent &event );
     void OnFileActivated( wxFileCtrlEvent &event);
 
-    virtual void UpdateControls();
-
 private:
-    // Don't use this implementation at all :-)
+    // if true, don't use this implementation at all
     bool m_bypassGenericImpl;
 
 protected:
+    // update the state of m_upDirButton and m_newDirButton depending on the
+    // currently selected directory
+    void OnUpdateButtonsUI(wxUpdateUIEvent& event);
 
     wxString               m_filterExtension;
     wxGenericFileCtrl     *m_filectrl;
@@ -98,6 +99,7 @@ protected:
 
 private:
     void Init();
+
     DECLARE_DYNAMIC_CLASS(wxGenericFileDialog)
     DECLARE_EVENT_TABLE()