If you enjoy the three-pane look of a desktop e-mail client, but use Gmail, today is your day. Google just announced a new Labs feature, Preview Pane, allowing you to view and reply to e-mails while navigating your inbox. The feature is also available to Google Apps users.
As Google mentions, the new look will be familiar to iPad owners, who currently enjoy this three-pane view on their devices.To get the new look, go to Gmail > Mail Settings (upper right) > Labs. Scroll down to "Preview Pane," enable it, and save your changes.
Once enabled, a new button will appear in the upper right of your inbox. To toggle between the old-fashioned Gmail inbox and the preview pane, click the button on the left.
You also have the option to arrange the preview pane vertically or horizontally, using the drop-down menu on the right.
Google also added a 3-second delay before marking conversations as read; however, you can change that to immediately, 1 second, or never by visiting the general settings.