Appearance Options
Appearance options for all contours can be controlled here. changes to the colour opacity here will effect all contours equally. Use these settings to quickly set all contours to the same colour for example.
To restore all contours to their original colour, click on the reset button next to the colour selection button.
Visibility
The visibility checkboxes in the All Contours section turn on and off the mesh faces and wireframes, and contours for all regions of interest in the dataset. You can change individual visibility for each contour, however the options here will force these visual elements on or off.