sencha touch keeps content and overlays it

i have got problems: http://www.burning-emotions.at/shop/ 1234567 user pwd 1234567

When changing between the tabs, someti开发者_如何转开发mes it keeps the content and overlays it,...is this a bug of sencha touch or what am i doing wrong?

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when you are tapping on the next tab in that handler hide the previous panel by using hide() function and show() the required panel