Index: openacs-4/packages/acs-subsite/www/permissions/perm-modify.tcl
===================================================================
RCS file: /usr/local/cvsroot/openacs-4/packages/acs-subsite/www/permissions/perm-modify.tcl,v
diff -u -N -r1.8 -r1.8.2.1
--- openacs-4/packages/acs-subsite/www/permissions/perm-modify.tcl	23 Apr 2018 21:32:46 -0000	1.8
+++ openacs-4/packages/acs-subsite/www/permissions/perm-modify.tcl	26 Oct 2022 14:20:35 -0000	1.8.2.1
@@ -8,23 +8,28 @@
 
 permission::require_permission -object_id $object_id -privilege admin
 
-# entried in 'perm' have the form "${party_id}_${privilege}"
+set mainsite_p [expr {$object_id eq [subsite::main_site_id]}]
 
+#
+# Entries in 'perm' have the form "${party_id}_${privilege}"
+#
 foreach elm $perm {
-    set elmv [split $elm ","]
-    lassign $elmv party_id priv
+    lassign [split $elm ","] party_id priv
     if { $priv ne "remove" } {
         set perm_array($elm) add
-    }
+    }        
 }
 
 foreach elm $perm {
-    set elmv [split $elm ","]
-    lassign $elmv party_id priv
+    lassign [split $elm ","] party_id priv
     if {$priv eq "remove"} {
-        foreach priv $privs {
+        foreach priv $privs {            
             if { [info exists perm_array(${party_id},${priv})] } {
-                unset perm_array(${party_id},${priv})
+                if {$mainsite_p && $party_id == "-1"} {
+                    util_user_message "#acs-kernel.The_Public# $priv: #acs-subsite.perm_cannot_be_removed#"
+                } else {
+                    unset perm_array(${party_id},${priv})
+                }
             }
         }
     }
@@ -53,8 +58,7 @@
     #  nothing: Do nothing
     #  add:     Add the privilege
     foreach elm [array names perm_array] {
-        set elmv [split $elm ","]
-        lassign $elmv party_id privilege
+        lassign [split $elm ","] party_id privilege
 
         switch -- $perm_array($elm) {
             remove {
@@ -72,7 +76,7 @@
     ad_script_abort
 }
 
-set message [expr {$changes_p ? [_ acs-subsite.Information_Updated] : ""}]
+set message [expr {$changes_p ? [_ acs-subsite.Permissions_Updated] : ""}]
 
 ad_returnredirect -message $message $return_url
 ad_script_abort