>>The string is
>>
>>'Message ID: 1440202'
>>
>>and the character next to : is tab
>
>Then, it should now work with the tab as well.
>
>Thanks

Sorry, right after tab is one space and then a number in FF 3.6

Also, is it possible to not perform transformation in PRE tags?

Message ID:{space}{tab}{space}number

Also, I re-checked - it's space, tab, space, number.