What is the active Editor? That is the Editor in which you have the

mouse cursor located by the time you trigger a shortcut.

That is important because sometimes you will use a particular shortcut

for a task, and you only want to update data from a particular Editor. For

instance, you might want to erase a keyframe inside an Editor called

Timeline. You must place the mouse cursor above the Timeline Editor to

erase data in that Editor.

To erase anything in Blender, you can either press the X key or

DELETE. Both shortcuts will erase data like 3D models and keyframes.

If you have a 3D model selected and also a keyframe in the Timeline,

and press the DELETE key. What will Blender erase?

If you have the mouse cursor above the 3D Viewport, the 3D model will

vanish from your project. To erase the keyframe, you must press the key

when the mouse cursor is above the Timeline.

The concept of an active Editor is essential for all shortcuts in Blender.

With the active Editor, you can choose where to apply a keyboard

shortcut.

1.4 3D Navigation and zoom controls

The 3D Viewport is the most important Editor in the Blender user

interface regarding modeling and visualization of your 3D data. In this

Editor, we can also use several tools and shortcuts to successfully

navigate the 3D space. Blender uses a combination of mouse and

keyboard shortcuts to navigate in 3D.

Here is a list with the most common shortcuts for 3D Navigation: