Only the activeTab in an ExtJS 2.3.0 TabPanel is scrollable, the other are not

Question

I have a TabPanel with 3 Tabs. When I set the first Tab active (activeTab: 0) it is scrollable, but the other 2 are not. When I change activeTab to 1, only the second Tab is scrollable, but the first is not anymore. How can I get all 3 Tabs scrollable? Here is part of my Code:

    new Ext.TabPanel({
            autoTabs: true,
            activeTab: 1,
            deferredRender: false,
            border: false,
            enableTabScroll:true,
            defaults: {autoScroll:true},
            items: 
            [
                 {
                     title: 'Profil-Liste',
                     items: [profileForm]
                 },{
                     title: 'TestGrid',
                     items: [testGrid]
                 },{
                     title: 'Geraete-Liste',
                     items: [geraeteForm]
                 }
            ]
        }),