_sweep1 (interface bug, minor), no frame style, no preview

No Idea how it happens, nor how to reproduce:
but it seams to be possilbe (Mac, Version 7 (7.11.21271.01002, 2021-09-28) that the sweep1 dialog starts with no Frame Style and no Preview.
as soon as i klick on one of the Frame-style options i get a result.

but the command should start with a default frame style, or the last frame style