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, 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

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, 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