As many of you know, we got rid of the live preview last week. Originally it was intended to just be a test to see if it was causing severe posting lags on very slow computers, but it turns out that most of the regulars prefer not having it (either that, or the original novelty of it greatly wore off).
Therefore, some of you may have discovered that for the past few days there is a little green checkmark in the top right of the editor toolbar. You can click it to generate a preview that also spellchecks. As before, click the preview to hide it.