Your problem is probably caused by Chrome reworking, as the position:fixed elements handle z-index stacking. The change was made for Chrome v22 , so if you built on v21 and use position:fixed , you may have a problem.
They suggested testing by clicking the Chrome special URL about:flags Chrome in the browser and setting Fixed position elements create stacking contexts. to true (for v22 +) or false (for v21).
You can recycle your CSS by making sure that the position:fixed elements position:fixed correctly. Unfortunately, this is a bit complicated, so we recommend that you read them for a better explanation:
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