+void wxCalendarCtrl::UpdateMarks()
+{
+ // we show only one full month but there can be some days from the month
+ // before it and from the one after it so days from 3 different months can
+ // be partially shown
+ MONTHDAYSTATE states[3] = { 0 };
+ const DWORD nMonths = MonthCal_GetMonthRange(GetHwnd(), GMR_DAYSTATE, NULL);
+
+ // although in principle the calendar might not show any days from the
+ // preceding months, it seems like it always does, consider e.g. Feb 2010
+ // which starts on Monday and ends on Sunday and so could fit on 4 lines
+ // without showing any subsequent months -- the standard control still
+ // shows it on 6 lines and the number of visible months is still 3
+ //
+ // OTOH Windows 7 control can show all 12 months or even years or decades
+ // in its window if you "zoom out" of it by double clicking on free areas
+ // so the return value can be (much, in case of decades view) greater than
+ // 3 but in this case marks are not visible anyhow so simply ignore it
+ if ( nMonths < WXSIZEOF(states) )