To delete a single message:
Click a message in the Message List or expand a folder and click a message in a folder, then click Delete on the toolbar, or click the DELETE key to delete a message.
To delete multiple messages:
Press CTRL and click multiple messages in the Message List or in a folder, then click Delete on the toolbar, or click the DELETE key to delete the messages.
- OR -
Press SHIFT and click the first and last message in a consecutive list of messages, then click Delete on the toolbar, or click the DELETE key to delete the messages.
Note: Messages will be deleted immediately unless you have selected Move to Deleted Folder in the User Preferences page.