I am noticing strange behavior with the layout panel in beta 5. When switching between different screens sizes I get different results of the preview pane. Such as I pick 4 column layout for tablet and then on the preview it only shows two columns. I have to physically go in and add the columns for them to show up in the preview. I have added a video to show this in action.
Video Link:
https://app.box.com/s/xt5qsh7tramptd4pcadrse6043tegnd1