It is not possible to copy a normal text from an E-mail from "Thunderbird" and paste it into "XF-Editor" at "Private Conversations".
using Firefox version 30.0
write some text.
edit message and delete some text.
paste some text from "Thunderbird" into the Editor.
The strange thing is:
sometimes it is possible to paste the text into the Editor, sometimes not.
I am not sure how to re-produce it, but "copy/paste" via "Strg+C" and "Strg+V" is not working properly in the Editor.