You can customize toolbars, menus, keyboard, and your IntelliMouse (if you use one).
You can invoke the Customize window at any time by right-clicking in any blank toolbar area.
Note: If you prefer an older interface for customizing toolbars and menus, select UI Themes, and select the classic interface.
Whenever you make changes to the UI settings it is best to save the Workspace file (under the Options tab accessed via Tools|Customize) in order to accurately retain your changes.