The Diff Merge display varies, depending on whether the tool is used within the context of a merge or is used only to compare files, directories, or versions.
If used within the context of a merge, Diff Merge displays two or more contributor panes and one merge results pane. (If you are merging HTML contributors, Diff Merge displays an HTML browser pane above or below the contributor panes.)
Contributor panes show the file or directory contents of a given contributor to the merge. These panes are arranged either horizontally or vertically and are numbered. The base contributor (labeled Base in the title bar) is the first contributor, the to-version (labeled To-version in the title bar) is the last contributor, and all other contributors appear between them.
The merge results pane appears above or below the contributor panes and is not numbered. When you resolve differences between contributors, the changes appear in this pane.
The HTML browser pane (labeled Previewing in the title bar) renders and displays the HTML content of the currently selected contributor. The number of the contributor being displayed appears in the title bar.
When you use Diff Merge to compare elements, it displays only the contributor panes. There is no merge result pane. (If you are comparing HTML contributors, Diff Merge displays an HTML browser pane above or below the contributor panes.)