Sometimes content of "Installed languages" disappear

Binary package hint: language-selector

On Language selector when I open the "Install/Remove languages" window for the first time all ok, the second time there is nothing in the window.

I have identified the problem, only if I close the window by decoration close button (destroy event) the problem occurs. If I push "Cancel" button there are no issues.

Step to reproduce:
 - Open Language selector
 - Click on the button Install/Remove languages
 - Close the window by decoration close button
 - Click on the button Install/Remove languages

On terminal, after check for installed languages, application writes this:

/usr/lib/python2.6/dist-packages/LanguageSelector/gtk/GtkLanguageSelector.py:837: GtkWarning: gtk_cell_view_set_cell_data: assertion `cell_view->priv->displayed_row != NULL' failed
  cell = combo.get_child().get_cell_renderers()[0]
/usr/lib/python2.6/dist-packages/LanguageSelector/gtk/GtkLanguageSelector.py:804: GtkWarning: gtk_cell_view_set_cell_data: assertion `cell_view->priv->displayed_row != NULL' failed
  cell = combo.get_child().get_cell_renderers()[0]

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((Like the demonstration by induction unverified, base step ok, base step + 1 failed.))