The new jquery.panel.js still can not solve this problem.
I upload three simple files: layout.html, tabs_fit_false.html and tabs_fit_true.html, can be placed inside jquery-easyui-1.3.5/demo/layout to test. Open layout.html, click the button named 'load tabs_fit_false' , center-region has a scroll bar, and then click the button named 'load tabs_fit_true', center-region cancel its scroll bar, all work fine now. But I reclick 'load tabs_fit_false' button, scroll bar will not reappear, because class "panel-noscroll" has not been removed from 'center-region'.
1. click 'load tabs_fit_false'
2. click 'load tabs_fit_true'
3. reclick 'load tabs_fit_false', scroll bar will not reappear