I'm trying to use the spoiler toggle button for a sales thread of mine, but it doesn't seem to work when I preview it? I'm typing it the same way I see it in HTML code threads ( [ spoiler ] -- just w/o the spaces) but it just shows it as the code before the text and doesn't actually show the button for me to hit?

Is it supposed to do this and will show the button after I hit "post" or am I just doing something wrong? ^^'