Dialog modal=True doesn't seem to work

I'm attempting to use Dialog in a modal manner inside a full screen application where I've already bound things, such as @kb.add('o'). When I create the Dialog, I add in modal=True to the arguments. However, when I trigger this dialog to display, those key bindings (such as o) are still sucked up and the dialog doesn't behave like a modal.

 39     dialog = Dialog(
 40         title=title,
 41         body=HSplit(
 42             [
 43                 Label(text=text, dont_extend_height=True),
 44                 textfield,
 45                 ValidationToolbar(),
 46             ],
 47             padding=Dimension(preferred=1, max=1),
 48             modal=True
 49         ),
 50         buttons=[ok_button, cancel_button],
 51         with_background=True,
 52         modal=True
 53     )

Further, dialog.container.container.is_modal() evaluates to False with these parameters.

Not sure what to do at this point as the base key bindings (which I would like to keep) interfere with simple typing into the box.

Start by reproducing the Dialog construction with modal=True alongside the existing @kb.add('o') binding. Inspect the Dialog/container path and check why dialog.container.container.is_modal() is false. Done means the modal dialog accepts text without the base key bindings consuming those keystrokes.