It seems to me that about the same time that the buttons (Code, Bold, etc) stopped working, the reply box stopped allowing to select text.
I've tested with IE and it works as expected, but in Chrome it appears that I can't select any of the text I've just typed.
To be more accurate I can select but it get de-selected right away. Same thing happens when selecting with mouse, shift + , shift + ctrl + arrows, shift + home, shift+end,etc. Ctrl + delete or Ctrl + backspace works fine.
It's not a huge issue, as I mostly need it when writting code and then trying to insert it into "code tags" or format or what you call it nowadays.