AUI_CONTROL enhancement: to delete all the children of a dialog or other parent control, you can now use CTLOP_DEL with parentid set to the id of the parent whose children are to be deleted, and all other parameters set to null, e.g.
xcall AUI, AUI_CONTROL, CTLOP_DEL, NUL_CTLID, NUL_CTEXT$, NUL_CSTATE, NUL_CTYPE, NUL_CMD$, NUL_FUNC$, NUL_CSTATUS, NUL_SROW, NUL_SCOL, NUL_EROW, NUL_ECOL, NUL_FGC, NUL_BGC, NUL_FONTATTR, NULL_FONTSCALE, NUL_FONTFACE$, NUL_TOOLTIP$, parentid
This is nearly equivalent to using CTLOP_CLR and setting ctlid to the parent control id, except that in this case there is no possibility of some child controls being protected.
