Per-molecule animation settings are used to change the dynamic behavior/appearance of the selected molecule.
Animation settings are changed through the Animation-Per-Molecule Settings menu which opens the Animation Preferences dialog.
The UI controls on the dialog are enabled if and only if the molecule can be animated i.e. if vibration or trajectory information is available.

Animation - On/Off - Enable/Disable animation for the selected molecule.
Animation Mode - Choose animation mode between Trajectory and Vibration.
Time step - Set the animation time step in milliseconds for this molecule.

Scaling factor - Frequency multiplier, vibration speed is multiplied by this value.
Show arrows - Hide/Show arrows. Arrows are used to display the direction of motion and speed of individual atoms.
Constant arrow length - If checked all the arrows have constant length; enabled only when Show arrows checked.
Arrow scaling - Arrow length scaling factor; enabled only when Show arrows checked.
Frequency Table - Shows the vibration modes read from file; the current vibration mode can be changed by clicking on the corresponding row.

Direction - Forward/Backward - Change the direction of motion.
Loop Mode - Changes the way animation is repeated.