Comparing Resources
  When a comparison is performed, comparison editors appear in the editor area. The differences between files are
  highlighted in the comparison editors, allowing you to browse and copy changes between the compared resources.
  To compare resources:
  
    - Select one or more resources in one of the navigation views.
- From the resource's pop-up menu, select Compare With.
A tool for viewing differences is opened in the editor area.
  Here are some of the comparisons that you can perform.
  
    - Compare With > HEAD revision
- compares the selected resource with the version of the same resource that is currently committed to the active
    branch. This option is available for Git. This or a similar option, may or may not be available for other
    repository types.
- Compare With > Another Branch or Version
- compares the selected resource with a version that has been committed to the repository or to the latest
    version in a particular branch. This requires you to choose a version of the resource or a branch from a list. 
    This or a similar option, may or may not be available for other repository types.
- Compare With > Each Other
- compares two or three selected resources with each other
- Compare With > History...
- compares the selected resource with a version of the same resource that was committed to the active branch.
    This action will open the History view in compare mode. You will then be able to choose which revision you
    wish to compare by double clicking on a revision in the History view. This or a
    similar option, may or may not be available for other repository types.
- Compare With > Local History
- compares the selected resource to one that is in the local history, which is maintained when you save changes.
    (Tip: to configure the size and depth of your local history, use the 
     General > Workspace > Local
    History preference page.) General > Workspace > Local
    History preference page.)
Tip: You can customize the behavior of the comparison editor with the 
   General > Compare/Patch
  preference page. You can select to "synchronize scrolling" of the pane contents, as well as setting options for
  showing conflicts with other team members and changing the default font.
 General > Compare/Patch
  preference page. You can select to "synchronize scrolling" of the pane contents, as well as setting options for
  showing conflicts with other team members and changing the default font.
  
  Three way comparisons
  Local history
  Synchronizing with the repository
  Merging changes in the Compare editor
  Resolving conflicts
  Setting preferences for comparing files
  Comparing resources with repository versions
  Understanding the comparison
  Working with patches
  Tiling editors
  Compare editor