Link of a lookup field
When the link from the description of a lookup field is called, the target dataset is not opened as a new level but via a new page (as if the corresponding dataset had been opened from the sub area).
If no visible sub area is defined for the lookup field, this leads to the opening of the target dataset in a new level. If the dataset with the lookup field has not yet been saved and the relation has not yet been created, this also leads to the opening of the target dataset in a new level.