7. Layers Panel
Hidden by default use "View/Panels.../Layers" to show this panel.
The Layers panel provides a shorthand way to work with sets of objects.
Layers are useful to divide a complex scene up into manageble parts. For instance all your background models could be put in one layer, you you can easily hide them all while working on the foreground models.
Each little grey rectangle represents a layer. Each object is assigned to a layer by right clicking on one of the grey rectangles while the object is selected. A layer is hidden and unhidden by left clicking.
Using Layers
The current selected object is in the Active Layer represented by a vertical white bar.
Layers with Objects in have a horizontal white bar.
Hidden layers are displayed in dark grey.
You can Show, Hide and Select layers by number using the white text buttons, just drag on each to open a layer menu.