Last 2 bars are small. How do I resize them?

I am using 1.1 and have created a new score using the "Piano" template. I have defined 24 bars and used the "Break every x bars" plugin to limit each line to 2 bars. However, as shown in the attached pic, the last two bars are not extending across the page.

How do I resize these bars so they are the same as the previous bars, i.e. the full page width?

Thanks,
Paul