This flat out doesn't work most of the time. I suggest you make what people really want, a Double Click to Close Tab add on where if you left double click a tab on the bar it will close. This is a very poor replacement for that great legacy add on.
Unfortunately it is not a replacement for the extension you are thinking of ;-) As already mentioned in the description, it is replacement for "Rights to Close" legacy extension.
Can you provide any more details? Your OS, Firefox version and an example website where it didn't work for you?
