Pre_Field userexit at each field in a mask.
The userexit cch_skp_fld is the only userexit which -- installed at the Pre_Field trigger -- is not only executed in Insert and Update mode, but also in Query and in View mode.
With this userexit single fields can be simply locked from editing without having to modify field access attributes.
Fields positioned outside forms (negative column position) are automatically skipped. It is not required to use cch_skp_fld.