prevent crash if panel/kicker is killed, bug 1872724

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/branches/WX_2_8_BRANCH@53563 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

include/wx/unix/taskbarx11.h

@@ -36,6 +36,9 @@ public:
 protected:
     wxTaskBarIconArea *m_iconWnd;
 
+private:
+    void OnDestroy(wxWindowDestroyEvent&);
+
     DECLARE_DYNAMIC_CLASS(wxTaskBarIcon)
 };
 

src/unix/taskbarx11.cpp

@@ -276,6 +276,14 @@ bool wxTaskBarIcon::IsIconInstalled() const
     return m_iconWnd != NULL;
 }
 
+// Destroy event from wxTaskBarIconArea
+void wxTaskBarIcon::OnDestroy(wxWindowDestroyEvent&)
+{
+    // prevent crash if wxTaskBarIconArea is destroyed by something else,
+    // for example if panel/kicker is killed
+    m_iconWnd = NULL;
+}
+
 bool wxTaskBarIcon::SetIcon(const wxIcon& icon, const wxString& tooltip)
 {
     wxBitmap bmp;
@@ -286,6 +294,9 @@ bool wxTaskBarIcon::SetIcon(const wxIcon& icon, const wxString& tooltip)
         m_iconWnd = new wxTaskBarIconArea(this, bmp);
         if (m_iconWnd->IsOk())
         {
+            m_iconWnd->Connect(wxEVT_DESTROY,
+                wxWindowDestroyEventHandler(wxTaskBarIcon::OnDestroy),
+                NULL, this);
             m_iconWnd->Show();
         }
         else