bug discovered

[JJC3561]

I hope this might help someone out there ...

file topic.py. line 263: if index < 0 or len(topic_list) >= index: # THIS IS WRONG

should be
if index < 0 or index >= len(topic_list): #THIS IS CORRECT
or
if index < 0 or len(topic_list) <= index: #THIS IS CORRECT

[this is a mild bug :]

-- in normal situation, it will fail to "insertBefore()" and instead it will do "append()", when adding a new topic.
-- in unusual situations, if one tries to "insertBefore()" a new topic with a (mistakenly) large index, it will crash instead of fail over to "append()"