The ImBox widget randomizes triggers/views to all available agents being Online. This by distributing the visitors evenly between available agents.

Please note that not all visitors that see the chat choose to start a conversation and we can not know who chooses to start a conversation when they visit your website. This means that two chat agents could have been distributed with 8 visitors each, where all 8 of the visitors that are assigned to the first agent aren't at all interested in starting a chat while 5 of the visitors that's assigned to the second agent choose to start a chat. Hence, on a short term a slightly uneven distribution of chats could be experienced but usually evens out over time.