Symbol Spinner

Click or drag over the symbol instances you want to stain with the colorization color. The amount of colorization gradually increases, and the symbol instance’s color gradually changes to the colorization color.

Hold down Alt (Windows) or Option (Mac OS) as you click or drag to decrease the colorization amount and reveal more of the original symbol color.

Hold down Shift as you click or drag to keep the colorization amount constant, while gradually changing the color of the symbol instances to the colorization color.

9-slice scaling

https://creativepro.com/understanding-illustrator-s-9-slice-scaling/

essential for web graphics
9-slice scaling is useful only when applied to symbols that will be viewed with the Flash Player (as SWF).
Since it’s an effect applied in the Flash Player, you won’t be able to preview the result of a 9-slice scale unless you’re viewing your art in the Flash Player.


1. f8 - define a symbol
2. Enable Guides for 9-slice scaling. The symbol must be defined as a Movie Clip (Figure 1).

 you can preview the proper 9-slice scale result by checking Enable Live Preview from the Control menu.




4 guides create 9 different regions on the screen

middle - both horizontally and vertically

upper left, upper right, lower left, lower right are all areas that do not scale at all.

SOURCE:
https://creativepro.com/understanding-illustrator-s-9-slice-scaling/