@hughenknubbel @thomas Sure, promote properitary software here.

But I also don't see how it should adapt. Tried it out in Chromium and there is is just a rectangle moving around, so you would not see anything adapting.

What I think you mean is that the end and start of the scrollbar always adapt to the content (or only are visible in the visible area), but also Firefox' scrollbars seem to look the same at the start and in the middle, so I cannot make out any difference.

Also, generally saying. Better describe what you want here: https://bugzilla.mozilla.org
There is no ticket for "adaptive scrollbars" yet.

@alex