Disable preview in file open dialog.. how??

How do I disable the preview pane in a file open dialog (it seems to be the standard W7 open dialog with enabled preview)?

In Windows Explorer there are a button to turn it on/off, but not in a open dialog.
There doesn't seem to be any option to turn it off anywhere and Alt+P apparently doesn't.

I know it is possible as I found it by chance several months ago, but I've managed to to forget how.

I can't understand how they would add a preview pane without an obvious way to get rid of it (i.e same button as in explorer).

I've tried searching the forums, but I've only managed to find threads related to Windows Explorer, not the open dialog, and they seem to be different in behavior.

notsograymatter said:

If you're talking about the open dialog from within a program such as Paint, you can close the preview pane via a button on the top right of the open dialog.

That's what I'm talking about.. However, it seems the guilty part might
be Nero Vision Xtra, and not W7 itself as I initially thought.

It doesn't have that button, and Alt+P doesn't work.. which is very annoying indeed.
Either it starts playing the inside the preview, or it just consumes space.

Both of which are not useful at all.

I've attached a snag of the dialog.