defines whether the marked(blocked) time spans should be highlighted in the scheduler
scheduler.config.display_marked_timespans = false;
...
scheduler.init('scheduler_here',new Date(2013,05,11),"week");
The property is available from version 3.5.
The property requires the limit plugin to be activated.
If you set the option to false, time spans will continue to be blocked, but will be displayed as usual scheduler cells.