Saves the current file to disk and erases its change history and undo history. You can think of this as a “clean” save operation. It has the same effect as saving the file, closing it, and opening it again. After using Checkpoint, you will not be able to undo any prior changes.
In versions of Source Insight earlier than version 3.0, this command was simply known as Save, because earlier versions did not preserve undo and change history after saving a file.