Use Band and BandIndex to control toolbar layout.
<ToolBarTray Background="White"> <ToolBar Band="1" BandIndex="1"> <Button Content="B1"/> <Button Content="B2"/> <Button Content="B3"/> </ToolBar> <ToolBar Band="2" BandIndex="1"> <Button Content="B4"/> <Button Content="B5"/> </ToolBar> <ToolBar Band="2" BandIndex="2"> <Button Content="B6"/> <Button Content="B7"/> </ToolBar> </ToolBarTray>
source share