Hi Alain,
I'm not sure what's up with that... Perhaps it's a browser compatibility thing because on THIS computer, running XP+FireFox 3.0.9 I get the ordinary Reply button below the last message, in the left corner - see screenshot:

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However, on another computer running Win7+IE8 I do NOT get the button in the same place, only at the top of the page even though I'm displaying the thread with newest message at the bottom on both machines.

/Henrik.