Unable to set Reply Prefix to nothing

[GoogleCodeExporter]

What steps will reproduce the problem?
1. Login using Witty and access the Options screen
2. Click in to the reply prefix ComboBox and delete the contents.
3. Click Done.

What is the expected output? What do you see instead?
Expected: Using reply feature then creates a reply without any Prefix.
Instead: The default prefix returns, it is impossible to set the prefix to 
nothing.

What version of the product are you using? On what operating system?
2.4.0.1844 on Windows 7 RTM

Please provide any additional information below.
While some people like to use prefixes, I prefer the default Twitter mode 
of not having one. Not being able to unset this is very annoying.

Original issue reported on code.google.com by nidon...@gmail.com on 24 Feb 2010 at 11:55

[GoogleCodeExporter]

i don't see any other twitter client (web or application) prefix a reply. and 
quite frankly the reply prefix has caused some confusion among my followers 
thinking tweets with such prefix (r > >> etc.) were re-tweets instead of 
replies.

Original comment by ivylee...@gmail.com on 15 Sep 2010 at 11:53