Copy some text with a trailing newline and paste into any textfield. The textfield appears to have ignored the paste, but in actuality the paste worked but included the newline as well, so the text isn't visible. Hit backspace to see what you would have expected. We should strip CR and LF characters when pasting into textfields. Assigning to Ryosuke because I'm not sure who owns this stuff and I figure he can triage.
*** This bug has been marked as a duplicate of bug 79305 ***