What
In lists of options you pick from, the up arrow is now checked before focus moves to the previous option. In some cases the key press is ignored instead of moving the selection.
Why
Pressing up at the top of a list may leave the selection where it is instead of moving it.
Something disagreesSomething we can check disagrees with this entry, or the writer said they could not settle it.
The writer flagged doubt
The finding does not say exactly when the up-arrow check applies or what happens to the ignored key press.