This thread is missing the point. It's not about intuition, it's about getting the job done. and when I select OR copy text from OpenOffice I expect it to be insertable in Mozilla Mail.
Alas, often it isn't. Often you get a few lines or a couple of paragraphs. Often you juist don't get the whole selection and you have to check if anything is missing, which is highly annoying.
I prefer selecting and middle-clicking, but that doesn't really matter to me. What matters is that either way you can't rely on the operation to succeed. And this is a Bug, a BUG, a BUG!