I have some questions regarding the concept of aria-haspopup and perhaps various nuances of the usage.
What is the basic concept for the usage of aria-haspopup? E.g. for a user such as myself (I’m blind and navigate mostly with VoiceOver), an element being visually «on top of other content» is nothing I can relate to. Unless, that is, if the popup restricts navigation outside of itself.
According to the WAI-ARIA 1.1 spec aria-haspopup can take on a range of different values. But from what I can tell, these values seem to be different «types». For example I think that «dialog» describes the container while «tree» describes the content. So what can we infer of the (behavior of the) container if we use «tree» as the value?
The HTML spec describes that the <dialog> element should contain navigation while ARIA says simply that the element with role=dialog (non-modal) should have at least one focusable element (see semi-related issue #794). What is the intended behavior of the container that the element that has aria-haspopup references and does this change depending on the values set?