The topic subscriber tab allows you to subscribe to topics on the selected broker. For each subscriber, a message buffer is kept to store the received messages.

On the upper left you see the broker selection box to select a broker to work with. This does not have to be the same broker as on any of the other tabs, SMM can connect to multiple brokers at the same time.

On the upper left, below the broker selector, is the list of subscribers. A checkbox before the subscriber name indicated whether this particular subscriber is active or not. An inactive subscriber will not receive new messages.

The lower half of the window is occupied by the message viewer. This displays the details about the currently selected message.