Gmail has got new layout, there is now a preview pane option in Labs. With this cool new feature included in Gmail users can now get  two-pane view which displays the email list as well as the currently selected message in either horizontal(New Yahoo mail like) or vertical split(iPad-like) view.
Steps to Enable Gmail Preview Pane
1. Sign-in into your Gmail account.
2. Goto Gmail Setting –> Click Labs section.
3. Search for Preview Pane.
4. Click on Enable radio button and hit Save Changes.
5. Once you’ve enabled it, there will be a new button on top of the email list which will enable you to activate the vertical split or horizontal split and switch between the full list view and the split view.
6. That’s it 🙂 .The currently selected message will be displayed in full to the right or below the email list.
And by default, messages previewed in the pane are marked as read after three seconds. 🙂
