Some ChromeVox features don't currently work with a second display, in particular the focus ring, and touch accessibility.

Speech seems to be okay. If you focus things between different displays you get the right feedback.

The visual focus ring is not correct. If you focus something outside of a webpage (like the location bar or status tray) on a second monitor, no focus ring is drawn. If you enable ChromeVox Next (Focus a web page and then press Search+Shift+Q+Q), no focus ring is drawn on the web either.

Touch accessibility is broken too, coordinates aren't transformed properly.

To test from a Linux development device, you can open two displays inside windows like this:

out/Release/chrome --ash-host-window-bounds="801+0-800x800,0+0-800x800"