Hi,
There is a bug with the editor that I noticed and others noticed too. When you post a very long code segment (or maybe just a long post, period), at some point it seems to overflow the capacity of the editor and you can no longer scroll all the way to the end of the post. The scroller becomes weird and jumps around, but you can never get to actually see the latter end of the post in the editor. You can still edit the content after where the editor stops, and that content still turns up in the final post, but you can't see what you are writing (except through the live preview, which is of course not viable for that purpose).