Layers are one of the most powerful features in CAD, and using them efficiently can make a huge difference in how a project evolves and is managed in time. In HighDesign, layers can be quickly accessed through the Layers pane on the sidebar, that lists all the project layers and provides quick access to some basic functions for their organization and use.
One of the most recent features added to HighDesign is the Mask Others command, available via the Organize menu or the button on the Layers pane.
When you activate the command, all the other layers except the current are turned off, allowing you to isolate the elements on that layer for revision and editing.

Mask Other Layers acts as a switch: for as long as it is active, you can activate any layer and all the others will be masked automatically, so you can use the Layers pane to browse through your project layers for a more through and time-effective revision of the project. Moreover, when you switch it off it restores automatically the visibility of all the layers exactly as it was before the command!
A very powerful command under a tiny icon!