Hide, show dialog query select button.

[VORP]

Method showQueryValues is called upon dialog initialization(/Classes/RunBaseDialogModify/Methods/init - (623, 10)), depending on it query button will be added. So if you modify it when dialog already initialized nothing happens. You should hide button manually, maybe looking at initQuery methods will be useful. But event after that you need to reset query if required, because it will be used even if its invisible.