How to add hidden button in replies?

mj1919

Hello Friends
How to add hidden button in replies?
in first post of each threds (actually starter post of threat), author can use hidden codes (if enabled, code below, as a button, in pic 1).
but other users that post replies in this threds can not use that button, (they can type hidden code manually, but threre is not any hidden button in reply text editor!),
how can i add this hidden button to reply posts?

Thank you

1. [hide][/hide]

Copy the Code

pic1, first post of threds


pic2 reply posts