After enabling 'Auto check text' for a domain, I see no way to revert to manual.

After disabling for a domain, I see no way to re-enable.

Does not work with the editable field when writing a comment at GitHub.

Workaround:

1. switch from write mode to preview mode
2. re-select the previously selected text
3. reuse the extension
4. revert to write mode.

Tested with Waterfox 56.2.0.31 on FreeBSD-CURRENT.

Enhancement request:

- please make the extension work with the context menu for selected text.

(It's rarely good to _require_ use of the toolbar, or overflow menu.)

Thanks