Navigate and Merge Three-Way Differences
With three-way comparisons, you can navigate differences between the three panes in a similar way as with two-way comparisons, from the Diff and Merge menu and toolbar. For example, you can run the Next difference (Alt+Down) 
command to navigate to the next difference and Previous difference (Alt+Down) 
to navigate in the opposite direction, see also Navigating Differences.
Unlike two-way comparisons, three-way comparisons may result in conflicts and also require special merging commands (for example, to copy a difference from left to middle pane, or from middle to right). All the commands specific to three-way comparisons are available in the 3-Way Comparison toolbar. This toolbar appears automatically when a 3-way comparison is toggled on. You can also explicitly show or hide it from Tools | Customize | Toolbars tab.
3-Way Comparison Toolbar
The 3-Way Comparison toolbar contains the following commands:
 | Previous Conflict | Jump to the previous conflict. |
 | Next Conflict | Jump to the next conflict. |
 | Copy from left to middle | Copy (merge) the current difference from the left pane to the middle pane. |
 | Copy from middle to left | Copy (merge) the current difference from the middle pane into the left pane. |
 | Copy from middle to right | Copy (merge) the current difference from the middle pane to the right pane. |
 | Copy from right to middle | Copy (merge) the current difference from the right pane to the middle pane. |
 | Change document order (Swap panes) | Enables you to swap the left or right pane with the middle one, see Swapping Panes. |
Note the following:
•The commands above are enabled only if they are meaningful for the current difference or conflict. For example, the commands "Copy from left to middle" and "Copy from middle to left" are disabled if the current difference is between the middle and right panes (but not the left one).
Other commands that can be issued in the context of three-way merges are the same as for two-way merges, namely:
•To undo a merge change, first click inside the pane where you want to undo the change, and then run the Edit | Undo menu command (or Ctrl+Z keyboard shortcut). The same applies for the Edit | Redo menu command (and its respective Ctrl+Y keyboard shortcut).
•To save any merges made from DiffDog to a file, click the Save 
or Save As 
buttons at the top-right corner of each pane. To reload the file content from the disk (and thus lose any unsaved changes made from DiffDog), click Refresh 
). See also Editing Files and Saving Files.
•Differences resulting from three-way comparisons can be exported to an XML or text file, see Exporting Differences.