Minor Example of bug:
private List<String> cmdparam = Arrays.asList("slist","sadd","sdel"); @Override public List<String> onTabComplete(CommandSender sender, Command cmd, String label, String[] args) { if (args[0].equalsIgnoreCase("")) { return cmdparam; } }
return only the first character in this example i write /ri and hitting TAB and that return ri s
see picture below 
