Unable to resubscribe to channels in team

If a channel is unsubscribed from, then you reopen the "manage channels" window, the channel is checked even though it is not subscribed to, thus removing your ability to subscribe to that channel again.

The issue identifies the manage channels window and the unsubscribe/resubscribe sequence, but names no source files or tests. Start by reproducing the behavior in a team with a channel, then trace the manage channels UI and its subscription state. Done means an unsubscribed channel is unchecked and can be selected to subscribe again.

Written by the indexing model from the issue text.