You are right. Setting the autocomplete attribute to "off" does not disable Chrome autofill in more recent versions of Chrome. ... <看更多>

<form autocomplete="off" method="post" action=""> <input autocomplete="false" name="hidden" type="text" style="display:none;"> ... This formation is going to ... ... <看更多>

The values on and off are supported, but the autofill behavior depends on the browser. When you set the autocomplete attribute, the lightning:input component ... ... <看更多>

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The solution appears to be to wrap the language selector in a form element and add autocomplete="off". Adding this to the starter should make it more robust ... ... <看更多>