When using a screen reader (such as ChromeVox) to navigate Moodle, some of the dialogue boxes will close when trying trying to wrap to the top of the screen reader.

This was discovered while testing MDL-35918.

When a dialogue is opened it should lock the screen reader's focus within the popup to allow them to navigate it. When the screen reader hits the end of the page (in this case the dialogue) it will offer to wrap to the top of the page. When selecting that option it should shift the focus back to the top of the dialogue box but instead it will close it.

To replicate the issue use ChromeVox to open up a help dialogue within Moodle, navigate to the end of the dialogue using the screen reader until you hear "wrap to top". Select the wrap to top section (hit enter) and it will close the dialogue. What it should do is just shift focus back to the top of the dialogue.