thx
i have tried the new demo and i see what i dit wrong 1 calendar can have just 1 timetable

but i have changed the code and when i run it everything goes good of _calendar
i mean the month vieuw ,week view,but when i click on timetable i get the timetable of _calendar so thats good but the timetable1 and 2 also have  a "V" in the view menu i have changed the view menu but he stil gives only the _calendar and not the other two

Private Sub _menuView_Popup(ByVal sender As Object, ByVal e As System.EventArgs) Handles _menuView.Popup

       _menuMonth.Checked = (_calendar.CurrentView = CalendarView.SingleMonth)
       _menuMonthRange.Checked = (_calendar.CurrentView = CalendarView.MonthRange)
       _menuWeekRange.Checked = (_calendar.CurrentView = CalendarView.WeekRange)
       _menuDayRange.Checked = (_calendar.CurrentView = CalendarView.DayRange)
       _menuTimetable.Checked = (_calendar.CurrentView = CalendarView.Timetable)
       MenuItem1.Checked = (Calendar1.CurrentView = CalendarView.Timetable)
       MenuItem2.Checked = (Calendar2.CurrentView = CalendarView.Timetable)
    End Sub

no the example that you gave me is good
i know that each calendar could have only one timetable so i did it whit visible true and false for hiding or schowing a calendar
but the problem is that even i put the code visible true / false to it he only want to show te first _calendar

Private Sub _menuMonth_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles _menuMonth.Click
       _calendar.Visible = True
       _calendar.CurrentView = CalendarView.SingleMonth
       Calendar1.Visible = False
       Calendar2.Visible = False
    End Sub

    Private Sub _menuMonthRange_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles _menuMonthRange.Click
       _calendar.Visible = True
       _calendar.CurrentView = CalendarView.MonthRange
       Calendar1.Visible = False
       Calendar2.Visible = False
    End Sub

    Private Sub _menuDayRange_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles _menuDayRange.Click
       _calendar.Visible = True
       _calendar.CurrentView = CalendarView.DayRange
       Calendar1.Visible = False
       Calendar2.Visible = False
    End Sub

    Private Sub _menuWeekRange_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles _menuWeekRange.Click
       _calendar.Visible = True
       _calendar.CurrentView = CalendarView.WeekRange
       Calendar1.Visible = False
       Calendar2.Visible = False
    End Sub

    Private Sub _menuTimetable_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles _menuTimetable.Click
       _calendar.Visible = True
       _calendar.CurrentView = CalendarView.Timetable
       Calendar1.Visible = False
       Calendar2.Visible = False

    End Sub
    Private Sub MenuItem1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles _menuTimetable.Click
       Calendar1.Visible = True
       Calendar1.CurrentView = CalendarView.Timetable
       Calendar2.Visible = False
       _calendar.Visible = False
    End Sub
    Private Sub MenuItem2_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles _menuTimetable.Click
       Calendar2.Visible = True
       Calendar2.CurrentView = CalendarView.Timetable
       Calendar1.Visible = False
       _calendar.Visible = False
    End Sub

    Private Sub _menuLightBlue_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles _menuLightBlue.Click

       _calendar.ApplyTheme(Theme.LightBlue)
       Calendar1.ApplyTheme(Theme.LightBlue)
       Calendar2.ApplyTheme(Theme.LightBlue)
    End Sub

    Private Sub _menuLightBrown_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles _menuLightBrown.Click

       _calendar.ApplyTheme(Theme.LightBrown)
       Calendar1.ApplyTheme(Theme.LightBrown)
       Calendar2.ApplyTheme(Theme.LightBrown)
    End Sub

    Private Sub _menuStandard_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles _menuStandard.Click

       _calendar.ApplyTheme(Theme.Standard)
       Calendar1.ApplyTheme(Theme.Standard)
       Calendar2.ApplyTheme(Theme.Standard)
    End Sub

    Private Sub _menuView_Popup(ByVal sender As Object, ByVal e As System.EventArgs) Handles _menuView.Popup

       _menuMonth.Checked = (_calendar.CurrentView = CalendarView.SingleMonth)
       _menuMonthRange.Checked = (_calendar.CurrentView = CalendarView.MonthRange)
       _menuWeekRange.Checked = (_calendar.CurrentView = CalendarView.WeekRange)
       _menuDayRange.Checked = (_calendar.CurrentView = CalendarView.DayRange)
       _menuTimetable.Checked = (_calendar.CurrentView = CalendarView.Timetable)
       MenuItem1.Checked = (Calendar1.CurrentView = CalendarView.Timetable)
       MenuItem2.Checked = (Calendar2.CurrentView = CalendarView.Timetable)
    End Sub

"Are you sure the calendars don't share the same Schedule object ? "

wel i workt  on the sample that you gave me so you created 3 different calendars

_calendar-> the originaly
   
   Calendar1 -> new one
   Calendar2 -> new one

but if

"either change the Schedule of the Calendar object from the timetable1/2 menu item handlers, or use several Calendar instances and show/hide them when needed. "

then i must write a appart method just for showing hiding

they musnt be visible at the same time just when you klik on timetable 1 it must show calendar1 and when you click on timetable 2 calendar 2 must be visible
so i must create two additional Schedule instances and assign them to the Calendar.Schedule when another timetable should be made visible.

but i have still that problem whit when i select timetable that the two others are also selected
i thaugth if you set the two menuitems by menuView popup that they checked it and select just one timetable at the time

i know but i need a view of 3 timetables and in one calendar can be only one timetable or could you add there the 2 timetables whitout making the other 2 calendars

no the form is to small to split
so i will make each timetable visible true/false

so one timetable in the form

That should do it:

calendar.TimetableSettings.HeaderDateFormat = "'timetable' ddd MMM dd, yyyy";