In previews tags that Generate MathML do not have working source tooltips. The tips will work after posting, but not before. Also the calculators MathML display do have the same problem, but also lack source for the tooltips. The non-working in previews is because the jQuery that generates the tooltip code is run once on page load and not again after the update to the page. The fix would be to run the generation code again every time the page changes, which occurs every keypress in a preview and any time the enter key or '=' button is pressed in the calculator.
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