Mail List
This is the main window listing all the messages currently in your mailboxes.

At the top is a tab for each of the accounts you defined. If there are any messages in a specific account, the icon of the tab will change from to and the number of messages will be shown next to the account name.

Below the account tabs are the following buttons:
Preview the currently selected message. While PopTrayU is not a full mail client, it can provide a quick view of the message.
Delete the currently selected message. Depending on the Confirm Deletion options, you will be asked if you are sure.
Send a new mail message. This will open your default e-mail client, ready to send a message. If you drag and drop a file into PopTrayU, it will create a new message in your e-mail client, with the dragged files as attachments.
Reply to the selected message. This will open your default e-mail client with the current message's sender in the to: field and the subject filled in. It will not fill in the body of the message.
Hide/Show message you've already viewed in PopTrayU.
Delete all messages with the Spam icon from the server.  Messages are marked as spam either by rules, the black list, or manually by right-clicking and seletecting "Mark as Spam".
Check for new mail on the current account. If you shift-click this button, it will do a full check even when quick-checking is enabled.

You can right-click the toolbar to customize it to show the buttons you want.

Next is the list of messages in the currently selected account. You can click on the headers to sort the list by the column you click on. To remove the sorting, right-click and select No-Sort. You can also right-click on the columns to show/hide specific columns.

In front of each message is a little icon indicating the message status:
High Priority
Normal Priority
Low Priority
Protected Message. This message is protected against being deleted or marked as spam. This can be done using the whitelist or a rule with a protect action.
New Message since the last check
Message with a MIME Attachment
Ignored Message. This is a message that have been marked as ignore by a rule.
Important Message. This is a message that have been marked as important by a rule.
Message is marked as Spam (either by rule or black list).

Below the the list of messages is a status bar that indicates when PopTrayU last checked your mailbox. Any network errors will also be displayed here. On the right hand side the status bar will indicate the number of messages and the number of spam in the current account.

At the very bottom are three buttons:
Run the E-Mail client you defined in the options screen. The icon on the button will be set to the icon of your e-mail client.
Check all your enabled accounts.
Minimize Pop-Tray to the tray.