Calendar

ui.Calendar creates a month's calendar choosing the day of a *time.Time, as SwiftUI's graphical date picker: a click chooses a day, as the arrows do while the calendar has the keyboard focus; Page Up and Page Down, or its buttons, move by months, and Home and End go to the first and the last day of the month. Changed reports a new date, which keeps the time of day and the location of the value.

ui.Calendar(c, &app.day).Label("Due date")

It shows six weeks from the first day of the week of the user's regional formats (Context.Region: Sunday in the United States, Monday in most of Europe), the days of the months around in gray, and marks today. Its title ("January 2026", "2026年1月"), the names of the weekdays and the days' names for assistive technology are CLDR's in the window's language, its days in the language's digits; the buttons' names are MyGo's own strings.

For a date in a compact field, use a date input, which opens this calendar below it.

Browsing without choosing

Browse lets the user look about the calendar without choosing a day: its buttons and Page Up and Page Down only show other months, and the arrows, Home and End only move among the days, until a click, Enter or Space chooses one, as in a date input's calendar. Changed then reports only a day the user picked, as a calendar in a popover that closes when a day is picked needs:

chip := ui.Button(c, task.Due.Format("Jan 2"))
if chip.Clicked() {
	app.dueOpen = !app.dueOpen
}
ui.Popover(c, chip, &app.dueOpen, func() {
	if ui.Calendar(c, &task.Due).Browse().Changed() {
		app.dueOpen = false
	}
})

The calendar goes back to the value's month as the app sets another date.

Accessibility

Assistive technology sees a table named by its month, whose days are buttons named by their dates, the day chosen checked, and reads the day chosen as the arrows move; with Browse, the day the arrows are on.