Ghosts are helper objects that show poses and positions (in form of silhouettes) that a character assumes on the previous and subsequent frames, so you can see how the current pose fits with the animation in its entirety. The tool for controlling ghosts can be found in the interface panel at the top of the main window.
Ghosts can be rendered in a number of different modes. You can adjust them in the list on the Toolbar:
Disables ghost rendering
Shows ghosts of the previous frames
Shows ghosts of the subsequent frames
Shows ghosts of both previous and subsequent frames
Shows ghost of the frames selected on the timeline
Toggles Key Frame mode. If this button is enabled, every mode described above will only render the ghosts of key frames
Note: If the key frame mode is selected, a key symbol is shown near every icon on the list.
The number of frames on which ghosts are rendered can be set in the fields on the sides of the list. The left field is for setting the number of previous frames, the right one is for setting the number of subsequent frames.
These fields are disabled if Key Frame mode is set