You need ACCESSIBILITY_ENABLED=1before the chromium invocation. I don't think it works without that variable. Use the attached .desktop file to make it run correctly from your menu. Save it as ~/.local/share/chromium-browser.desktop.
This has the --enable-caret-browsing flag as well, since without it I was unable to select any text inside of the browser. If you want to be able to select and copy text, you need this flag.
~Kyle
Attachment:
chromium-browser.desktop
Description: application/desktop