Spark 2.7.0 has bug

Two chat windows are opened up for a same person to whom i want to send message.

It is enough to post in Spark Support. Next time do not post same issue twice.

Maybe one of this tabs is opened from the contacts list and another from a group chat room? Spark (and other xmpp clients) consider this as different entities, although the name could be the same. Have you tried to reproduce this with Spark 2.7.7?

No, i have not opened from group chat room. I have opened from contacts list only.

Strange. Haven’t seen such issue myself. Are you opening by double clicking on a contact? Can you reproduce this on another pc? Have you tried 2.7.7 version?