Assembly: Microsoft.VisualStudio.Text.Data (in Microsoft.VisualStudio.Text.Data.dll)
Mapping back to a previous version gives the same result as mapping forward from the origin version. This mode should be used only for short-lived points and spans.
Mapping back to a previous version (either by explicitly moving to that version or by undo or redo operations) may give a different result from the one that was originally given for that version. This mode is suitable for most purposes, and is the most space-efficient mode.
Mapping to a version that is the result of an undo or redo operation gives the same result as mapping forward to the version that underwent the undo or redo operation. This mode is more expensive thanin both space and time and should be used only if necessary.
For information about tracking, see the "Tracking Points and Tracking Spans" section of Inside the Editor.