Cant get tabpanel to fill max height

I am sorry, I have been trying to find a solution without asking. Everything I seem to try is failing. I just want the tab panel to take 100% height/width of its parent.

Code:

                       Ext.create('Ext.panel.Panel', {
                                renderTo: Ext.getBody(),
                                layout: {
                                        type:'fit',
                                        align: 'stretch'
                                },
                                items: [
                                        Ext.create('Ext.tab.Panel', {
                                                flex:1,
                                            items: [{
                                                title: 'Foo',
                                                html: 'Hello World!'
                                            }, {
                                                title: 'Bar',
                                                html: 'Testingggggggg',
                                                tabConfig: {
                                                    title: 'Custom Title',
                                                    tooltip: 'A button tooltip'
                                                }
                                            }]
                                        })
                                ]
                        })

Cant get tabpanel to fill max height