ExtJS Combobox with Checkbox

I want to design combo with checkboxes(display checkboxes along开发者_运维知识库 with dispalyfield) i tried lovcomb, but not getting is there any alternative for this or how to use lovcombo for multiple section

Thanks in advance

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Alternative method (with out checkboxes): http://technomedia.co.uk/SuperBoxSelect/examples3.html