I have just updated MB to the latest version 3.0.0. I find that though the sidebars flexible but the columns are set to take pre-fixed sizes. Is it possible to change the width to the desired size? For e.g. in the previous version I had set the sidebars to 165 and 300 respectively.
When compared with the previous versions the latest one is less compact and has more blank spaces. If the blank spaces can be reduced then the site can show more contents in less space.