Unwanted transformation of Chinese characters When I copy and paste character  it's transformed into the Japanese version, 禮 (radical 示 instead of 礻).

What's going on? Is this some 'feature' of Unicode? Is there still a way to paste the character  to a text document / Notes.app note? (After all, on the Wikipedia page linked above the character displays correctly — and as a character, not as an image.)

(Doesn't seem to depend on browser / text editor I'm using. OS X 10.9, if this is important.)
Han characters are unified in Unicode.  Display of the Chinese vs Japanese version depends on the font.  In OS X, the default font should normally be determined by the order of these two languages in the system preferences language list.  Make sure that Chinese is higher than Japanese on your list and restart.

It's possible some apps might not follow that and need font adjustment individually.