It is recommended that you hide unneeded regions while performing corridor edits.
For example, when editing a corridor that contains multiple regions, hide the regions that you are not editing. This typically results in faster system response time while editing a corridor.
The Show All Regions command restores the visibility of any regions whose visibility is currently turned off. The command is not available if all regions are visible.
The Isolate Region command turns off the visibility of all corridor regions, except the selected one. This command has the same effect as clearing all region check boxes on the Parameters tab of the Corridor Properties dialog box, except that of the selected region.
All corridor regions are again visible.