Blender Quick Tips: How to collapse the elements in the outliner?

Issue: Imagine you’re work on a complex project with numerous assets organized into collections and subcollections. As you attempt to select everything on the screen, you notice that every item in the outliner is unexpectedly expanded. Given the quantity of meshes in your project file, manually collapsing each mesh and collection would be a painful task.

The likely cause of this expanded view in the outliner is accidentally pressing the “+” key on the Numlock pad. Pressing this key in Blender’s outliner presents us with the following screenshot:

Luckily, it’s just as easy to tidy everything up again by simply pressing the ‘-’ key on the numpad!: