Listing 1

// left_percentage gets changed as the user moves the splitter
left_pane.left { 0 }
left_pane.width { parent.width * left_percentage }
in_between.left { left_pane.width }
// the space between the panes
in_between.width { 10 }
right_pane.left { in_between.left + in_between.width }
right_pane.width { parent.width - left_pane.width - 10 }