Modern messengers allow you to transfer any communication online, whether relatives, friends or co-workers. Sometimes in one application several dozens of active chats accumulate and the search for the most important of them takes a long time. The function of fixing the selected chat at the beginning of the list solves this problem and is not new for instant messengers. For example, in Telegram the number of attached conversations can reach 5, in Viber - more than 10. WhatsApp developers just started testing this function in the closed beta version of the application.
You can fix both individual and group chats, but not more than three simultaneously. Perhaps in the final version this number will be increased. When you lock chats at the top of the list, the remaining conversations, even if there are unread messages, will be located below them.