Open Radar

 
Summary: In Safari, when using the Reader feature to read a website, you can't use the spacebar to page through the text.

Steps to Reproduce:

1) Open Safari
2) Go to a website; let's go to "http://www.collectorsweekly.com/articles/please-feed-the-meters" , but every website with longer articles will do
3) Press the spacebar repeatedly and notice that with every press the page scrolls down a page minus one line. 
4) Now press the big blue Reader button, on the right of the toolbar.
5) The article is now presented in reader format, without ads and distractions.
6) Now press the spacebar again
7) Boom! Notice that we scrolled all the way to the bottom of the long scrollview.

Expected Results: Pressing the spacebar in Reader mode would scroll a page minus one line for every key press.

Actual Results: Pressing the spacebar in Reader mode scrolls all the way down to the bottom of the page.

Regression:

Notes: This works also in almost all other Mac apps that present non-editable content, it might be a feature of NSScrollView. Mail, Preview, Xcode documentation viewer, etc, etc.