How to create tabbed browsing like firebox in qt

[prabhatjha]

!http://i.stack.imgur.com/DPVtB.png(image)!

hello everyone i am working on web browser in qt ....i made tabbed browsing like google chrome and firebox its working fine ...but when i am trying to open new window everything working fine but when i opened a new tab in new window initially its working fine but when i came back to my earlier window the new tabbed button take space of earlier window so new tab button positioning being mismatch...so if u have any solution please give ur valuable sugession.