Oh wait, I think I understand what you mean 
- Write down the following markdown
[code]
line1
line2
[/code]
- Select the text and click the “Blockquote” button so it prepends a
>on each line
> [code]
> line1
> line2
> [/code]
Which renders (wrongly) as
line1 line2
Instead of
line1 line2
This is most likely an issue with the way we parse BBCode Blocks 