The new Gmail Preview Pane will help readers to preview the message of a new mail landed in Inbox while reading or replying to others. So, with Preview Pane, which is available in Gmail Labs, users can see the new mails without opening it.
The Preview Pane makes it easy for Gmail users to stay up to date with all their mails. While you are busy with composing a long mail to your friend or customer, simultaneously you can see the content of the new mails. So, if you receive any mails that need urgent response, you can save the mails which you are working in drafts and open the new mails.
Users can activate Preview Pane from Google's experiment site, Google Labs. By activating Preview Pane, users can see three-window panel, Navigation pane - Preview pane - Email pane. According to the type of the screen, users can change the settings of Preview pane. By selecting horizontal split, Preview pane can be placed on top and emails below, and the vertical split brings it to earlier version.
Meanwhile, this new Preview Pane has some negative effects - it may disturb you while composing any important mail as you get tempted to read the preview of the new mails. Moreover, some of the technology writers complained that the new Preview Pane made Gmail to a ugly and cluttered look. Also, some of them opinionated that the three-window panel for Gmail makes it difficult to work on low resolution screens.