The points on the coordinate lists can be locked against overwriting or deleting. The locking of the point is signalized by a sign of a lock in the left part of the coordinate list (before the point number). The points can be locked in two ways:
Individual points
While editing a point (e.g. by pressing the key <Enter>), whether or not it should be locked can be selected as one of the point features.
If you have turned on the option Settings->Environment: Fast point locking/unlocking, you can lock and unlock the individual points by clicking the mouse at the left border of the list (in front of the point number).
Batch locking/unlocking
The entire coordinate list or the selected points can be locked or unlocked using batch editing (command Coordinates->Batch edit).
The locked points can't be deleted or overwritten. You can change them only by the point editing (for example using the key <Enter>) or after their unlocking. If adding a point with a number which already exists on the list, and if such point is locked, a standard dialog window with information on the coordinate differences is displayed, but only the option to keep the original point on the list without any change is available.