I have assigned some moderators to my certain forums
I want to stop them to edit my/admin's posts .
I checked all the permissions in forum permissions options and group permission options
But there is no settings or options to do this .
Is there any way to do it ?
Tell your mods to keep their hands off your posts and if they don't comply, send them to hell.
Only make people moderators that you trust!
Can't it be achieved by edit any php code ?
This is a social issue, not a technical issue. If you can't trust your moderators not to respect the powers you give them and respect your wishes they shouldn't be moderators.
Consider template conditionals in postbit_edit whether to show button based on post author.
This should be considered technical. No one under an admin should be able to edit an admin's post. If that isn't in the code, maybe it should be added.
I looked at the code. Based on core code permissions checking, the assumption is a moderator for the forum or a supermoderator has the rights as designated with their title. A plugin or core edit would expand the basic permissions. A simpler template-based solution has already been suggested.
As it's been explained elsewhere, don't expect added features in 1.8