Abstract: A window splitter bar system in a computer environment provides a control button in the splitter bar between two panes in a multi-pane window application. The control button is used to open and close the pane. It is clicked to close the pane when the pane is open. The splitter bar stays visible when the pane is collapsed, appearing stuck next to the window's outer edge with the control button remaining visible. The control button is then clicked again to open the pane. The splitter bar can also be dragged in order to resize the pane, with the system storing the location of all of the splitter bars on the screen for restoring a closed pane back to its open state. The user can also drag the splitter bar to open and close the pane. When a pane is closed and the user drags an item over the splitter bar, the pane automatically expands so the user can drop the item into the pane. Once the item has been deposited in the pane, it automatically closes.