On Android 2.2-4.0, if option's value are in russian there is a bug with autosuggest and search.
Suggest works only if you enter space, and then delete it. Search results in suggest will update only then you delete s symbol, nothing is shown then you enter new ones.
Search only works if there is a space in option's value AND if there is a space in query. If one of this conditions is not meet, search will not work. But even if it works it works very strange — it will find all options that includes first word, but entered part of the second word is ingored.
How to reproduce:
"Адмирала На" -- will find Адмирала Макарова "Адмирала Нахимова" -- will find Адмирала Макарова "Адмирала" -- will find Абаканская If you enter "Александра Сергеевича А" suggest will find all options with word "Александра", but search will only find "Александра Сергеевича" — the first option.
Url with live test : https://github.com/leonid-d/chosens-bugs
Chosen is now disabled for Android mobile devices by default (as well as iPod and iPhone). There are too many issues and the native controls on those platforms are far more usable than selects in a desktop browser.