Hi,
I pasted the combobox plugin as it appears in the example in a VT created with krpano tools.
I'm not sure if I understand right - is your question also about to hide the combobox and show a custom icon or about general usage?
for general usage I would recommend the plugin documentation:
http://krpano.com/plugins/combobox/#top
if you were adding the combobox to a tour that was build with the MAKE VTOUR droplets - then also add - keep="true" - to the <plugin> element to avoid that the combobox plugin will be removed when the first scene will be loaded,
best regards,
Klaus