Adding Button in StatusBar !

try this

<StatusBar Height="32" Margin="10,10,61,0" Name="statusBar1" VerticalAlignment="Top" ClipToBounds="True" ><StatusBarItem><Button Margin="0,0,0,0" DockPanel.Dock="Left" >Button</Button></StatusBarItem><StatusBarItem>TEST</StatusBarItem><StatusBarItem>TEST2</StatusBarItem><StatusBarItem>TEST3</StatusBarItem></StatusBar>