--- 0.10.3/trac/config.py
+++ 0.10.3mod/trac/config.py
@@ -174,10 +174,15 @@
             fileobj.close()
 
     def parse_if_needed(self):
+        # Sections to completely reload (to allow for options being removed)
+        sections_to_delete = ['ticket-custom']
+        
         # Load global configuration
         if os.path.isfile(self.site_filename):
             modtime = os.path.getmtime(self.site_filename)
             if modtime > self._lastsitemtime:
+                for section in sections_to_delete:
+                    self.site_parser.remove_section(section)
                 self.site_parser.read(self.site_filename)
                 self._lastsitemtime = modtime
 
@@ -185,6 +190,8 @@
             return
         modtime = os.path.getmtime(self.filename)
         if modtime > self._lastmtime:
+            for section in sections_to_delete:
+                self.parser.remove_section(section)
             self.parser.read(self.filename)
             self._lastmtime = modtime