Layer tabs are a great way of organising complex or busy designs. They enable you to group sets of layers according to their use within the file, making them easily accessible.
To create a tab, click the + button highlighted in the snapshot above. A small pop up will appear where you can name the new tab. Simply enter a title and press ⮐ (return key) on the keyboard to confirm the change. Any layers which are active when you click the + button will be added to this tab.
To change the setup of an existing tab, simply activate all the layers you want to be included and double click on the tab you want to add them too. Then press the pipette icon shown in the snap shot above. Alternatively, you can hold down ⌥ (option key) when double clicking on the tab and this will update the tab with the active layers.
Note: If you want to keep existing layers in a tab and add a new set of layers to this, you must activate the layers which are already in the tab in addition to those you want to add.
The movie below shows you how to add, edit and delete tabs: