You can compare two or three selected resources to show the differences between the resources. You can compare a file with one or two other files, a folder with one or two other folders, and a project with one or two other projects.
You can also compare one selected resource with other states in the local edit history, or with other versions of that resource. For more information on comparing resource versions, see Comparing Resource Versions
The result of the compare shows up in a compare editor in the editor area. You can browse through all the differences and copy highlighted differences between the compared resources. You can save changes to resources that are made in the compare editor.