I'm not aware of this option, but I agree with you that it should be controlled. I'll try to expand my search in the meantime, I looked here for disabling Del key and found only one old thread, which I don't think is good.

>Thanks Naomi. It is not exactly an open dialog. I was wondering if there is a registry option, or a security settings in the folder permission that can ban users from deleting files from the Open Dialog. Microsoft says they are focused on security. What the hell where they thinking when they exposed the complete explorer interface in the Open Dialog? And if you use Terminal Server is even worse the case.
>
>>>Is there any way that the user cannot delete fiels (or copy-paste them) in the Open File Dialog box? I can disable the context menu through a Group Policy, but can I disable the delete key?
>>>
>>>Thanks a lot,
>>>Javier.
>>
>>Check Re: Open dialog to select file? other than getfile()? Thread #1039373 Message #1039391