Timeline Preloader animation

[federicoco]

Hello,
I would like to propose this feature : can timeline be equipped with a neat preloader?
You could put a simple preloader(with a function to toggle or not the animation preloader like true = show preloader and meanwhile load the graphics in that 1-2 seconds, false = don't show the preloader and do like we always did).

Could it be a feature ?

[mojoaxel]

see also #2306