This is a very handy view that outlines where items are on your page. You can click on the item in the Layout Tree View and the corresponding item on the page is selected. Or click on the item on the page, and the same item will highlight in the Layout Tree View. This can spare you from losing information on your page and having to revert back to the default layout.
Customization Text and Field Customization Text Views
All of the fields on the form are listed in the Layout Tree View in the format Customization Text (Field Customization Text), i.e., Username (User Name) and ILLiad Authentication (ILLiad Authentication). The first name displayed is the Customization text, which preserves the original field name as it would normally display on the form without any customizations. There are some exceptions, as in the Merge Users form, where these fields are designed to differentiate the new user from the existing user, i.e., New Username (Username) and Existing Username (Username). The field customization text displays what appears on the form by default or as it has been edited in the client or Field Customizations table.