When replying to a message, I often like to intersperse my responses with the relevant sections of the original message. When I try to do that in Thunderbird, it extends the quote line way above the quoted text. There appears to be no way to delete the "excess" section of the quote line without removing the quote line entirely.

Also, when there are two previous messages in a thread, there is only one quote line next to both. I cannot find any setting, nor any manual way of increasing the quote level of the original message.