This option provides the ability to cancel a variety of messages. What you right click on and the options you check will determine which messages are canceled.
For example, if you right click on the Groups heading and select this option, this will cancel messages for all groups. If you right click on a specific group's name, this will only cancel messages for the selected group.
•Cancel all pending messages
This option cancels messages in the pending queue for immediate delivery. This will not cancel messages scheduled to go out at a future date and time.
•Cancel all scheduled messages
This option cancels messages scheduled to go out at a future date and time. This may cancel messages scheduled by a repeating message but will not delete repeating messages from going out at a later time.
For example, if you have a message set to repeat every hour, enabling the "Cancel all scheduled messages" will cancel the message for the hour you're in but the next hour's message will still queue for delivery.
•Cancel all repeating messages
This option cancels messages scheduled to repeat.
For example, if you have a message set to repeat every hour, enabling the "Cancel all repeating messages" option will stop that message from ever happening again.