I noticed a strange behaviour of $crlf in the editbox when you use tab to replace the identifier:
1) type $crlf in the editbox
2) hit tab, instead than replace the identifier the cursor moves between the 'c' and the 'r' ($c|rlf)
3) hit tab again, 'rlf' disappears (it remains only $c|)
4) hit tab again, the $c disappears too
--
1) type $crlf in the editbox
2) hit tab, the cursor moves between the 'c' and the 'r' ($c|rlf)
3) hit a random key on the keyboard (numbers, letters, symbols, canc, backspace, spacebar and maybe others), the char is inserted between the 'c' and the 'r' and the message will be sent on the channel (for example, if you hit 'u', '$curlf' will be sent).
--
1) type foo $crlf in the editbox
2) hit tab, the string disappears
3) hit a key, for example 'a', on the channel will be sent 'foo' and 'a' on two lines

Is it normal?
It would be better if the tab on $crlf will show two "rectangles" as in //say $crlf.
It will be also nice adding an option to use the $crlf in the edit box so I can write/paste two sentence with a $crlf in between and send them to the chan on two different lines (as it happens with xchat).

Tested with mIRC v6.3 on WinXP SP2