diff -Naur software-properties-0.82.2.ori/softwareproperties/SoftwareProperties.py software-properties-0.82.2/softwareproperties/SoftwareProperties.py
--- software-properties-0.82.2.ori/softwareproperties/SoftwareProperties.py	2012-01-11 10:53:05.000000000 -0500
+++ software-properties-0.82.2/softwareproperties/SoftwareProperties.py	2012-01-30 17:15:46.743118962 -0500
@@ -660,6 +660,9 @@
     if parsed_uri.netloc == 'ppa.launchpad.net':
       worker = AddPPASigningKeyThread(parsed_uri.path, self.options and self.options.keyserver)
       worker.start()
+      return worker
+    else:
+      return None
 
   def update_interface(self):
     " abstract interface to keep the UI alive "
@@ -693,10 +696,13 @@
     new_debsrc_entry = SourceEntry(debsrc_line, file)
     if new_deb_entry.invalid or new_debsrc_entry.invalid:
       return False
-    self.check_and_add_key_for_whitelisted_channels(deb_line)
+    worker = self.check_and_add_key_for_whitelisted_channels(deb_line)
     self.sourceslist.list.append(new_deb_entry)
     self.sourceslist.list.append(new_debsrc_entry)
     self.set_modified_sourceslist()
+    if worker:
+        worker.join(30)
+        self.KeysModified()
     return True
 
   def remove_source(self, source):