Sometimes that button resets somewhere else from where it was originallywhere....but only if you edit the form and go thru it again.
IF everything is set OK on your final go-thru...don't edit again, because it will probably reset.
IF you have an error in the form that requires you to edit the 1099-R for some other reason, then yeah...you'll have to redo your selection.
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NC used to have 5 or 6 "seemingly" different selections on that page...and the top three all ended up putting an "N" (for State nontaxable) on a backup worksheet. Thus all three selections were really doing the same thing.