Single selection actions:
Open - opens the selected revision of the file into the Editor. This is enabled only for files.
Open with ... - Displays the 'Open with...' dialog for specifying the editor in which the selected file will be opened.
Save revision to - saves the selected revision to a file so you have an older version of that file. This option is only available when you access the history of a file, and it saves a version of that one file only.
Compare with working copy - compares the selected revision with your working copy file. It is enabled only when you select a file.
Update to revision - updates your working copy resource to the selected revision.
Check out from revision - gets the content of the selected revision for the resource into local file system.
Revert changes from this revision - reverts changes made in the selected revision.
Double selection actions:
Compare revisions - compares the two selected revisions using the Compare view. It is enabled when the resource is a file.
Revert changes from these revisions - similar to the svn-merge command, it merges two selected revisions into the working copy resource. This action is only enabled when the resource history was requested for a working copy item.
For more information about the History view and its features please read the sections Request history for a resource and Using the resource history view