Thunderbird refuses keyboard input after changing windows


my name is WendelinNordlicht and I am a beta-user. I am not quite sure whether anybody else has already complained about the topic before. If so, I do apologize.

When composing an email, everything is fine unless the user does leave the composing window. When changing back to the composing window, he or she can not resume the work but only having the draft saved and reopen it.

I am confident to say that Thunderbird is to blame as I run into it on different installations (computers) during different occasions.

Is there anybody out there who also got stuck with that issue?