a blank event is the same as "system every tick" event
It has no conditions so it is performed every tick..
Replacing the every tick events in this capx is hardly an effort..
Also adding an event to check if the new value is different from the one before would be the same as using "on changed"
The big advantage of doing it this way is that no Dom elemnts are used, Dom elements float above the canvas.
I'n not sure how easy it is to use css to change the appearance of the slider-bar object and how much freedom C2 allows in this case..
If you were to set the slider-bar invisible and use sprites to influence it, it would be much the same as the link I gave except for the extra slider-bar object..