Reading and managing emails is one half of the story. Composing them is the other half, and Gmail just went in for an improvement there. We could open a separate window to write a new email earlier too by clicking “Shift” while clicking the Compose button, using the Shift+c shortcut or clicking the pop-out icon. Using a separate window to write emails allows you continued access to your inbox. Gmail believes that this wasn’t used by many, and so they have gone about improving it so it is more prominent and gives you more control.
The Compose window has been redesigned to be faster and easier to use. The new Compose gets its own chat-like (but larger) pop-up window. You don’t have to close your draft to reference or read other emails. As it works like a chat window, you can write multiple messages at once and minimize a message to finish it later.
You can now also see profile pics of your contacts in the address field as auto-complete kicks in. You can drag and drop the new address ‘chips’ between the To, CC, and BCC fields. When all recipients have been added, the address area collapses automatically to get out of your way. Other changes include a new icon for text formatting, an icon for attachments and a “+” icon for embedding photos, links, emoticons and Google Calendar events.
Improvements have also been made to the way you reply. The changes are being rolled out gradually. To try the new interface, open Gmail, click the Compose button and look for the new compose experience link right next to the Labels button. You can switch back to the old interface if you don’t like the new interface.
Source: Google Operating System Blog