MotionBuilder Shelf
You can easily access the frequently used objects in MotionBuilder through the shelf instead of looking for these objects in the user interface. You can click an object in the shelf to add it to your scene immediately.
To display the shelf, select Open Reality 
Tools Shelves. The following figure shows the shelf.
You can use the File tab in the shelf for creating a new file, opening a new file, and saving a file. You can use the other tabs to access the default elements, primitives, characters, constraints, and devices.
The source for the shelf plug-in is saved in