Rated 4 out of 5 stars

Works great with Dictionary Switcher 1.0.1 (will most likely work with Dictionary Switcher 1.3.1, however that version doesn't work correctly with Firefox).

Simply install desired dictionary's and use Dictionary Switcher to change to the desired dictionary to spell check the page in any language, not just the default language.

Only problem I found is the text color for enabled/disabled does not follow the installed theme, black for off, dark green for on.