I posted an idea previously about having responsive grids collapse to tabs if the entire grid is too wide for the frame as an option to wrapping to the next line. An additional idea is to allow any single division to be collapsible. When collapsed, the division would shrink from its original width down to 5 or 10px wide and display an expand icon that the user could click to expand the division back to its original width. I use an application that utilizes this and it is really handy when you want 3 divisions, but the main division is best used at full screen width. So you could have a left division that is 25% of the screen width, a right division that is 25% of screen width, and a center division that is 50% of screen width, but then if you collapse the left and right divisions, the center expands to take up their width.