Unlink the root item
void PtFSRemoveList( PtWidget_t *fs, PtFileSelItem_t *first );
This function unlinks the item first and its brothers (together with their children) from their parent (and previous brother) and sets their parent fields to NULL.
The fs argument must point to the PtFileSel widget that contains the items, or be NULL if the items don't belong to any file selector.
|If fs is NULL and first has no parent but has a previous brother, the function won't be able to find the previous brother and therefore can't unlink first from its previous brother.|