customize bugzilla fields & User Permissions

[Khokhar]

I have one product and several components of this product. Each
component have several reported bugs.

Every bug has been assigned to a specific user who belongs to specific
group.

These group has very limited access ( and not a member of any other
group), but the users of this group still can edit bug fields.


I want to customize some text fields/areas for those users, so that
they can not edit that specific field.

I also want to customize some text fields/areas for for Bug Creator
(who files the new bug) so that he/she can not edit his/her posted
bug.
(I also want to hide some text fields and want to add new text
fields )


I had a look at this document and make the following changing
(comments) in Bug.pl file but nothing happens.

************************************************************************************
# Allow anyone to change comments.
#if ($field =~ /^longdesc/) {
# return 1;
#}

# At this point, the user is either the reporter or an
# unprivileged user. We first check for fields the reporter
# is not allowed to change.

# The reporter may not:
# - reassign bugs, unless the bugs are assigned to him;
# in that case we will have already returned 1 above
# when checking for the assignee of the bug.
# if ($field eq 'assigned_to') {
# $$PrivilegesRequired = 2;
# return 0;
}
# - change the QA contact
# if ($field eq 'qa_contact') {
# $$PrivilegesRequired = 2;
# return 0;
}
# - change the target milestone
# if ($field eq 'target_milestone') {
# $$PrivilegesRequired = 2;
# return 0;
}
# - change the priority (unless he could have set it originally)
# if ($field eq 'priority'
# && !Bugzilla->params->{'letsubmitterchoosepriority'})
#{
# $$PrivilegesRequired = 2;
# return 0;
#}
# - unconfirm bugs (confirming them is handled above)
# if ($field eq 'everconfirmed') {
# $$PrivilegesRequired = 2;
# return 0;
# }
# - change the status from one open state to another
# if ($field eq 'bug_status'
# && is_open_state($oldvalue) && is_open_state($newvalue))
# {
# $$PrivilegesRequired = 2;
# return 0;
#}
*****************************************************************************************



Is it possible what i want to do ?

Can we customize these fields via making changes in code ? or by Admin
side ? or by installing some plugins ? or any other way ?

Thanks in advance.

[Khokhar]

>I had a look at this document and make the following changing
>(comments) in Bug.pl file but nothing happens.

http://www.bugzilla.org/docs/4.2/en/html/cust-change-permissions.html

and I am using version 3.6.3 on Windows 7.