Yes the issue is reproducable.

 

If you go to code view and type a series of lines containg  the word Image and then try to change that to image, you get locked into a loop and can only escape that loop by closing Firefox through the Task Manager.

 

This only happens if Match Case is not selected. Ideally there should be an escape that does not involve having to close the browser through Task Manager.

 

I am using Vista, which obviously may be part of the problem.