The keys clipboard is a temporary storage area for keys and animation curve segment information. Storing new information on the keys clipboard replaces any information previously on the keys clipboard.
The same keys clipboard in Maya is available throughout all editors and windows. For example, information placed on the keys clipboard with a Cut operation in the Graph Editor may be pasted onto an object in the scene view using Edit > Keys > Paste Keys.
The keys clipboard is not an editor nor is it viewable in any window in Maya. Exiting Maya clears the clipboard.
