Call wxAuiManager::UnInit() if associated frame is destroyed

Don't require the application code to explicitly do it if the frame is
destroyed before the manager itself.

include/wx/aui/framemanager.h

@@ -555,6 +555,7 @@ public:
 protected:
 
     // protected events
+    void OnDestroy(wxWindowDestroyEvent& evt);
     void OnPaint(wxPaintEvent& evt);
     void OnEraseBackground(wxEraseEvent& evt);
     void OnSize(wxSizeEvent& evt);

src/aui/framemanager.cpp

@@ -593,6 +593,7 @@ bool wxAuiPaneInfo::IsValid() const
 wxBEGIN_EVENT_TABLE(wxAuiManager, wxEvtHandler)
     EVT_AUI_PANE_BUTTON(wxAuiManager::OnPaneButton)
     EVT_AUI_RENDER(wxAuiManager::OnRender)
+    EVT_WINDOW_DESTROY(wxAuiManager::OnDestroy)
     EVT_PAINT(wxAuiManager::OnPaint)
     EVT_ERASE_BACKGROUND(wxAuiManager::OnEraseBackground)
     EVT_SIZE(wxAuiManager::OnSize)
@@ -914,6 +915,8 @@ void wxAuiManager::SetManagedWindow(wxWindow* wnd)
 {
     wxASSERT_MSG(wnd, wxT("specified window must be non-NULL"));
 
+    UnInit();
+
     m_frame = wnd;
     m_frame->PushEventHandler(this);
 
@@ -958,6 +961,7 @@ void wxAuiManager::UnInit()
     if (m_frame)
     {
         m_frame->RemoveEventHandler(this);
+        m_frame = NULL;
     }
 }
 
@@ -3951,6 +3955,12 @@ void wxAuiManager::Repaint(wxDC* dc)
         delete client_dc;
 }
 
+void wxAuiManager::OnDestroy(wxWindowDestroyEvent& event)
+{
+    if ( event.GetEventObject() == m_frame )
+        UnInit();
+}
+
 void wxAuiManager::OnPaint(wxPaintEvent& WXUNUSED(event))
 {
     wxPaintDC dc(m_frame);