You can perform a subset of the Message menu options on any mail message (whether selected or not) by choosing that option from an alternate pop-up menu that you bring up adjacent to the message.
Do this by placing the mouse pointer on a mail message and clicking the right mouse button. A pop-up menu appears from which you can select one of the valid options available for the given mail message.
The pop-up menu displays the number of the mail message and the options that are currently valid for that message. If multiple messages are selected, the pop-up menu displays the heading Selected messages instead of the numbers of the mail messages. Invalid options are dimmed.
To select one of the options, slide the mouse cursor down the menu and release it on the option you wish to select.
The options available in the alternate pop-up menu function similarly to their counterparts in the Message menu.