Version:            (using KDE 4.3.0)
OS:                Linux
Installed from:    Ubuntu Packages

How much my page scrolls when pressing PageDown/PageUp varies, based on the content and what program I'm using to work with it. Basically when i press PageDown it should scroll exactly one page down, right? But it doesn't. Even in the middle of a very long document, it usually scrolls a little less than a page. I assume that's because it's assumed to be more reader-friendly when there's a little overlap between the before and after situations.
Near the start/end of documents the thing gets more annoying. When i press pageDown when there's not a whole page left to scroll down to, the jump forces me to visually scan the page and search for the spot i stopped reading before hitting the key 

I think this is a better place to report this then at Ubuntu brainstorm, where i reported this earlier, see http://brainstorm.ubuntu.com/idea/21929/