This topic describes some commands that are provided only as customizable actions. You can assign them to a keyboard shortcut, a menu, or a button by using the Customize User Interface dialog.
Keyable Property
Keyable Property Toggle
Default key: None
In Track View, if you select any track or group of tracks, this command turns the keyable property on or off. If a selected track is not keyable, its children (sub-animations), if any, are toggled. For example, if you select a transform controller track, this command toggles the keyable property of all position, rotation, and scale tracks. If you select an object's track, its transform, parameter, and material tracks are all toggled. If the object is part of a hierarchy, all its child objects' tracks are also toggled.
This action can be undone.
Set Key
Clear Set Key Mode Buffer
Default key: None
While in Set Key mode, if you transform an object but haven't yet clicked Set Key, this shortcut undoes the transformation and restores the viewport to show the animation that existed before the change.
Another way to accomplish this is to move the time slider or to turn on Play.
Transforms
Create Position Lock Key and Create Rotation Lock Key
Default keys: None
A lock key is a key with Linear interpolation. If you create the lock key while an existing key is selected, it changes that key's interpolation from Smooth to Linear. (Different types of interpolation are described in Bezier Controllers.) You can create a lock key for position or for rotation.
Lock keys are useful when you want an object to be stationary, but smooth interpolation is causing it to "wobble" on its stationary spot.
Position to Zero
Default key: None
Like its counterparts on the Animation quad menu, this shortcut restores the object's position to the initial “frozen” pose (0,0,0).
Viewport Navigation
Pan Viewport
Default key: I (the letter “i”)
Pans the active viewport, centering it on the current location of the cursor.
You can use this shortcut while another command, such as Move, is active.
This action can be undone, using 
+Z.