Wish: provide sticky mode for movable elements

This wish originates from http://bugs.kde.org/show_bug.cgi?id=166839.

The good example of benefit of having sticky mode is moving panel items (KDE4). You click, you move, you click again to release. If there is no conflict (there is for example with classic d&d) sticky UI can be provided – it is much better for a11 reasons than extensive movement with LMB pressed all the time.

Widgets that can work in sticky mode – scrollbar (its knob), slider, splitter. Resizing window could also be sticky.

However, option for this is required because current UI is so long with us and because sticky mode is not for everybody. But it would help decrease strain from moving mouse (or any pointing device), so it would be relief to any handicapped person (including even me with just RSI).