On certain webpages, if you scroll down and click the mouse button, then the next time you hit the command (apple) button, the page jumps back to the top. This would typically happen if you use command-click to open new tabs: try to do that twice, and you find yourself back at the top of the webpage. Example page: Yahoo Finance! pages, such as: http://finance.yahoo.com/q?s=aapl
I'm guessing that this is a "feature" since it brings focus to the search box consistently and it works in Firefox as well.
As Chasen said above the behavior is caused by "autocomplete" script: http://us.js2.yimg.com/us.js.yimg.com/i/us/fi/yfss/js/autocomplete_container_ylc_yfi_20070924.js so the bug in my opinion is INVALID.
I agree that it returns focus to the search box at the top of the page, but for the Mac platform, I would still classify this as a bug. First, Safari 3.04 does not replicate this behavior. Second, and more importantly, if you scroll to the bottom of the page in order to command-click on several links, with the intent to open them in new tabs, you will be quite frustrated. Since command is shifting focus back to the search box (but only on certain webpages), the second time you command-click a link, you will lose your place in the webpage. Tab is the button assigned to shift focus to search boxes; command should not duplicate this behavior.
I tested the reported issue in WebKit r39474 and I cannot replicable the problem any more. So I assume the bug is fixed. Any confirmations?