**Place the "toolbar" on the left, and the information panel on the right.**

Why?

# The F-Pattern
This positioning emphasizes the natural left-to-right movement you mentioned—a user first reads the items in the "toolbar", *then* reads the detailed information.

This pattern, known as the [F-pattern](https://www.nngroup.com/articles/f-shaped-pattern-reading-web-content/), is a very common way that a user will process a page; users often prefer to scan the top and left side of pages. Aligning your layout with this instinct will provide a more natural feeling for your users.

### For example

This positioning is favored by several other types of applications which use an item-detail relationship. For example:

+ Email clients list messages on the left
+ Instant messaging clients, such as Skype and Google Hangouts, group conversations on the left
+ File explorers, including Windows Explorer and Finder, have top-level folders stuck on the left