The $width identifier has a small bug since mIRC 6.17.

//echo -a $width($chr(2) $+ $chr(2),Tahoma,9,0,1)
This used to echo "0" in mIRC 6.16 and before, which is correct, since 2 bold characters only are 0 pixels wide.

In mIRC 6.17, it echoes "18", which is incorrect.