Fix VclPtr issue in rptui::ONavigator

Window ( 7VclVBox()) with live children destroyed:
N5rptui13NavigatorTreeE()

Change-Id: I974f73afd7dd259135d9bfcd47dd6bc8e7cc0d40

reportdesign/source/ui/dlg/Navigator.cxx

@@ -911,6 +911,12 @@ void ONavigator::GetFocus()
         m_pImpl->m_pNavigatorTree->GrabFocus();
 }
 
+void ONavigator::dispose()
+{
+    m_pImpl->m_pNavigatorTree.disposeAndClear();
+    FloatingWindow::dispose();
+}
+
 } // rptui
 
 

reportdesign/source/ui/inc/Navigator.hxx

@@ -38,6 +38,7 @@ namespace rptui
 
         // window
         virtual void GetFocus() override;
+        virtual void dispose() override;
     };
 
 } // namespace rptui