Hi, after month of research and with the help of many, here is a vanilla multislider that supports jump on click and dragging:
multislider.pd (updated)
@emviveros's post gave the hint: A click can actually go to more than one struct, so i created rows and columns to get the click. From there the slider is set. The idea was to click on it again via click message to drag the sliders. But somehow it is not even necessary. It just does it.
Many thanks to @Balwyn, @whale-av and especially to @Jona, whose idea it was and whom i worked with on the problem from the beginning to the end.
The method still has some limitations and the patch some unresolved issues.
Anyhow, i think it works great. Enjoy and have fun with it!