Home Try Buy

30-day free trial for Windows (need Mac OSX?)



Designing the Postbox Accounts and Folders Pane

December 2, 2010

One of the most innovative features in Postbox is its Accounts and Folders pane, the UI element that drives your message view. It’s completely unique, and this post will dig into how and why it’s designed differently than other offerings.


When we founded Postbox, we wanted to create a product that simplified the email experience while providing more power and control. We looked at existing folder pane implementations and found two basic approaches:

Thunderbird’s and Microsoft’s Hierarchical Approach

A simple tree hierarchy of accounts and their subfolders.


  • conceptually the easiest to understand, similar to file systems
  • all account data is grouped together
  • ability to keep all folders open and accessible


  • no support for unified inboxes or folders
  • difficult to jump from inbox to inbox
  • requires frequent expand/collapse actions for folders and subfolders
  • expanded folders increases the number of drop targets and folder pane scrolling


Apple’s Unified Folder Design

Apple’s design is optimized for viewing email within unified special folders such as the inbox, drafts and sent.


  • unified views for inboxes and special folders
  • ability to select individual accounts when needed
  • easy to jump from inbox to inbox


  • conceptually harder to understand since account data is broken up by special/functional folders
  • unified views include all email accounts, which inappropriately mixes work and personal messages together
  • difficult to navigate from folder to folder when working within a single account

(Note: in Thunderbird 3, Mozilla implemented Apple’s design and made it an optional view.)

A New and Improved Design for Postbox

Postbox Folder Pane

In Postbox, we wanted to give people the best of both worlds, which included unified folders and the ability to keep work and personal messages separate. The design also needed to be quick and easy to setup, organize and maintain. 

To address these challenges, we split Accounts from Folders and positioned them within their own dedicated panes. The Accounts pane is where you set context, for example, by selecting “work” vs. “personal” accounts.

When an account is selected, only the folders that belong to that account will display, and folders from non-selected accounts will be hidden from view. This dramatically simplifies the Folder Pane, minimizes the number of drop targets, reduces folder pane scrolling, and keeps unrelated contexts (e.g., work and personal) from inappropriately mixing.

To support Unified Views, all accounts are initially positioned within an “All Accounts” group. Selecting this group provides a unified view of all messages across all accounts in the selected folder. Additionally, special folders such as the inbox, sent, drafts and trash are also unified.

Most importantly, custom unified views can be created by organizing accounts into Account Groups. For example, you can create groups for your “work” and “personal” accounts, and then unify your message views by those groups.

With the basic design in place, we arrived at two decision points. The first was whether to display sub-folders within special folders, as illustrated below:

Postbox Special Folders

We solicited advice from Postbox users through several rounds of surveys, and from 986 responses, 56% selected the simpler option on the left.

Next, we needed to determine whether storage folders should be located at the root folder level, or positioned within parent folders named after the accounts:

Postbox Storage Folders

In this case, survey data indicated that Postbox users preferred the nested approach.

To wrap up, the design of Postbox’s Accounts and Folders Pane offers these unique benefits and tradeoffs:


  • ability to create groups of unified accounts/folder views to keep work and personal messages separate
  • quick to jump from group to group, account to account, and inbox to inbox
  • ability to keep folders within a group open and accessible
  • unrelated folders are kept out of view, which simplifies folder pane viewing and handling
  • clean, simple, flexible, and powerful


  • small learning curve associated with using two selectors instead of one
  • when a single account is selected, moving messages to another account requires a drag-hover-drop action as opposed to drag-drop

We think it works pretty well, what do you think?

Posted by Postbox