Edit Flight Plan Position
You can enter any string but all invalid characters will be removed when saving as a FSX/P3D PLN file. Other file formats have more limitations.
Allowed are upper and lower case letters, digits, underscore
_ and space. All other characters are removed when the flight plan is saved and long names are truncated to 10 characters.
You can also edit the coordinates directly in this dialog besides using the drag and drop Map Flight Plan Editing. This can be useful if you'd like to add waypoints with well known coordinates like visual reporting points.
The tooltip of the coordinate input field shows the available formats.
See Coordinate Formats for more information.
Picture above: Editing an user-defined flight plan position.