The Close command closes the current file. If the file has been edited, but not saved, then Source Insight will ask you if you want to save the changes before closing the file by using a dialog box with the following buttons.
Yes
Click to save and close the file.
No
Click to close the file without saving it. Changes you've made will not be saved.
Cancel
Click to cancel the Close command. The file will remain open, and it will not be saved.