14. The non-transitory computer-readable storage medium of claim 13 having contents configured to further cause a computing system to: in response to synchronizing from the second data structure to the first data structure a range of text surrounding the distinguished range of text in the second data structure, update a third data structure that tracks portions of the second data structure stored in the first data structure to reflect the synchronization.
13. The non-transitory computer-readable storage medium of claim 9 having contents configured to further cause a computing system to: determine that the user input device has been used to select text corresponding to a distinguished range of text in the second data structure; and in response to determining that the user input device has been used to select text corresponding to the distinguished range of text in the second data structure, synchronize from the second data structure to the first data structure a range of text surrounding the distinguished range of text in the second data structure.