There's an added bar above the dropdown arrow on posts for me:
The added arrow only shows up in chrome (I'm in chrome beta). It doesn't show up in Firefox and it doesn't show up on Stack Overflow chats, only the SE 2.0 sites have the arrow issue.
closed as too localized by Time Traveling Bobby, kiamlaluno, jonsca, Pops♦, jadarnel27 Jul 31 '12 at 15:20
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As vcsjones suggested this is a result of the Zoom setting in one's browser. By resetting to default zoom; use ctrl+0 to reset zoom or ctrl+mousewheel to zoom in/out until the arrow is normal.
The chat arrow will turn back to normal once the zoom level is at default.