In many functions the file to be used is not asked, but is selected from the file element list using special rules. In some function a selection list is used. This list shows all files selectable by the user.
There are several different file types: vector file, terrain model, measurement line (ML-file), road geometry (RG-file), etc. Selected file type must be of right type, which has Used-flag on, but not Hidden-flag (in file element list). As an exception, terrain model can be Hidden and still selectable.
If the active file in file element list is of right type, the file is selected.
Otherwise the last file of right type is selected (is Used -flag on).
If not file is found, you’ll get a warning.
You can control the file selection by moving the file in the end of file element list or by setting the Hidden-flag on or Used flag off for the other files.