Please use this code to custom the removable icon.
<input class="easyui-tagbox" value="Apple,Orange" label="Add a tag" style="width:100%" data-options="
tagStyler: function(value){
return {class:'mytag'};
}
">
<style type="text/css">
.mytag{
padding: 0 4px;
}
.mytag .tagbox-remove{
display: none;
}
</style>