Script Summary: Allows “in_reply_to_status_id” and “source” fields to be modified directly.
Pressing [update] will perform a normal status update, whereas pressing [update (unchecked)] will update status without performing the usual checks, so that e.g. you may reply to a status without actually having to include “@user” in your reply.
The “source” field will only work if you enter one that is registered (e.g. twitterfeed, twhirl, etc.) i.e. you can’t just make up a source.
The current version is a quick fix: not very pretty, but it works.
Note: I originally wrote this script to make “in reply to” correctly link to the message on which “reply to user” was clicked. However this functionality is now implemented by twitter, so I revised the script to perform the functions mentioned above.