US Patent 7428709 Multiple-panel scrolling

In a scrollable user interface window including two or more panels, a single scroll bar scrolls all of the panels. Panels move in lock-step with one another at certain times, but not at other times, depending on whether the lock-step scrolling would cause blank areas to be displayed. If the user's scroll commands would result in a blank area of a panel being displayed, the scroll command is not performed; rather, the panel remains frozen in its current position, even while other panel(s) do scroll. Thus, the present invention ensures that useful content is displayed at all times in all panels, and no screen real estate is wasted due to scrolling operations.