When testing T5864 I noticed that the UI "feedback" is confusing if you choose a date not in the configured range. This probably occurs on configuration of dates in general (if they have an allowed range), but I checked it out only for the case of key generation.

If you choose a not appropriate date in the calendar sheet, it will not be taken over into the "valid until" line. I expect the user will think that the program is broken, as there is no visual feedback that a not valid date was chosen.

If you choose the date by typing, the behavior is even more confusing: The inappropriate date is displayed in the "valid until" line (it was typed directly there, not in the second date field below the calendar sheet). But the value is not used when creating the key. Instead, the next possible valid value is used. Without any feedback.

I propose to

• show invalid dates in another color in the calendar sheets (a different red than that of Sundays?)
• show a invalid date in red in the "valid until" line, if you typed it in
• some kind of text based feedback for a11y

Additionally it would be better to only display one text input line instead of two: one above the calendar sheet (thats the "real" line) and one below. Or if we do, they should either always display the same value (I suspect that that is not possible) or only one of them should accept direct input. That would logically be the one below, as there some check occurs on the date which is typed.