After downloading the source code, you can see the exact layout in the SingleExample.xaml file. Basically, there is a Grid panel with few column definitions. The contents of the example (the scheduleview in this case) is placed in one column and the configurator panel (RadExpander) is placed in another column. Both elements have some Min/MaxWidth settings that adjusts their size automatically when the configurator collapses or expands.
You can achieve the same behavior by using the following layout:
Note that I've used Borders to illustrate the layout, but you can replace these with any visuals you need (like RadScheduleView).
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