When hilighting text that involves multiple paragraphs and lines that are word-wrapped, occasionally the viewer glitches out and hilights the wrong text. This video shows the problem:
http://www.lexneva.name/misc/hilight_bug.avi
In this video, I'm looking at the "My Notes" section of my profile, which contains 3 paragraphs of text. At the start of the movie, I place my cursor on the blank line between the second and third paragraphs. Then I click and hold my mouse button down and drag the mouse up slowly to hilight text. As I get up into the first paragraph, suddenly the hilight jumps down one line. All I'm doing is moving my mouse up. Then I start at the end of the second paragraph and follow a similar process, and the text glitches again.
It seems like the proper text is considered to be hilighted for the purposes of copy/paste, but the rendering of the hilight is broken.