Scrollable has default index value set to 0.
Now, if I call seekTo function dynamically and pass the clicked index, which is also 0, onSeek function will not be executed at all because of this:

            /* all seeking functions depend on this */
            seekTo: function(i, time, fn) {

                if (i < 0) { i = 0; } 

                // nothing happens
                if (index === i) { return self; }

Well, "nothing happens" would be true only, if I called this function with the same index once again.
It's fine if you have already loaded your large images by using <img> tag, but it breaks if you load images dynamically and all are hidden by default, which is my case, because onSeek callback loads large images progressively.

Additionally, I used to call this.getIndex() inside the onSeek callback, but it's broken in new version as well, because index is updated AFTER the onSeek is actually triggered in seekTo().

Anyways, I will change default index value to -1 or null, because it will solve my problems, although I know it's not the best solution because other functions rely on this var. But I don't use them.