Among the things Linux is still missing in comparison to Windows there's autoscroll. In Windows, clicking the middle mouse button in any window with a scrollbar causes a set of arrows to appear where you clicked. Positioning the cursor around those arrows causes the view to move automatically. The arrows disappear when you middle-click again. I believe it would be useful if KDE had a system wide auto scroll system.

Reproducible: Always

Steps to Reproduce:
1. Open any application that has a vertical and / or horizontal scrollbar.
2. Click on the mouse wheel while holding the pointer over the field.
Actual Results:  
Nothing happens.

Expected Results:  
With autoscroll, arrows would appear and let you move the view with your mouse.

I've been told that by default, KDE reserves the middle mouse button for pasting. In that case autoscroll could be disabled by default, and the user given a choice if to replace it.

If someone isn't familiar with what exactly auto scrolling is, this feature is possible in FireFox as a builtin option. Open FF, go to about:config, and set general.autoScroll to true. Then click the mouse wheel in any web page which is long enough to use the scrollbar and see what happens. The idea is to have this as a KDE feature, usable for any window like in Windows.