I think Contro found an issue in the [ code=language ] forum-tag. When pressing the 'Select' link and copying the content to the clipboard, each line is prefixed with 4 spaces, the space the line numbering takes in the view. When using no language in the code tag, all seems to work just fine.
I'd qualify this as a bug in (probably) the plugin that handles this layout task for the forum.
Test it here:
A multi-line block of text hidden
in a code tag without
a language applied to it
Another multi-line snippet of text
it shows line-
any recognized keywords
Using the select link on the second code block and pressing Ctrl-C to copy to the clipboard, then pasting in an editor, each line has 4 excess spaces in front of it.
This shouldn't be an issue for most languages, but for Python it is, and for the other languages it is a nuisance, not quite easy to fix for non-programmers as they don't understand why it isn't working as expected...