The spellcheck
attribute is still poorly (if at all) implemented in browsers. For example, when I go to the page that you mention in Chrome 18 and enter misspelled words in the "This text area should be checked for incorrect words" box. The browser marks the "words" as erroneous. Double-clicking on any other word makes it marked as spelling. The explanation is that I had Spanish as a spellchecker language. Note. This language can be changed by right-clicking on the input and selecting the spell-checker options, but the change does not take effect until the page reloads.
So, check these settings in your browser. Note that a check box is set here that controls whether spell checking is used.
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