TestColoredCalendar::TestColoredCalendar()
{
	CtrlLayout(*this, "Window title");
	drop_date.WhenPaintDay = THISBACK(MarkDate);
	calend.WhenPaintDay = THISBACK(MarkDate10);
}

void TestColoredCalendar::MarkDate(Date date,Color& fg, Color& bg){
	int day = date.Get();
	if (day % 2 == 0) {
		fg = Color(255,0,0);
		bg = Color(255,100,255);
	} else {
		fg = Color(60,60,255);
		bg = Color(255,255,100);
	}
}

void TestColoredCalendar::MarkDate10(Date date,Color& fg, Color& bg){
	int day = date.Get();
	if (day % 10 == 0) {
		fg = Color(255,255,255);
		bg = Color(255,0,0);
	} else {
		fg = Color(0,155,155);
		bg = Color(230,255,255);
	}
}

public:
	Calendar();
	Callback1<Time &> WhenTime;
	Callback3 <Date , Color&, Color& > WhenPaintDay; // <== Inserted line

	static const Style& StyleDefault();

	void Reset();

public:
	typedef DateTimeCtrl CLASSNAME;
	Callback3 <Date , Color&, Color& > WhenPaintDay; // <== Inserted line
	DateTimeCtrl(int m) : cc(m) {
		drop.AddTo(*this);
		drop.AddButton().Main() <<= THISBACK(OnDrop);
		drop.NoDisplay();
		drop.SetStyle(drop.StyleFrame());
		drop.GetButton(0).SetMonoImage(Grayscale(CtrlsImg::DA()));
		cc.calendar   <<= THISBACK(OnCalendarChoice);
		cc.clock      <<= THISBACK(OnClockChoice);
		cc.WhenPopDown  = THISBACK(OnClose);
		cc.calendar.WhenSelect = Proxy(WhenSelect);
		cc.calendar.WhenPaintDay = Proxy(WhenPaintDay); // <== Inserted line
	}
	virtual void GotFocus()  { T::GotFocus(); drop.RefreshFrame(); }
	virtual void LostFocus() { T::LostFocus(); drop.RefreshFrame(); }
	virtual Size GetMinSize() const { return drop.GetMinSize(); }

					if (!WhenPaintDay.Empty()){
						WhenPaintDay(Date(y,m,d),fg,bg);
					}

					if(d == today.day && m == today.month && y == today.year)
					{
						fg = st.fgtoday;
						bg = st.bgtoday;
						fnt.Bold();
						special = true;

						curday.x = j;
						curday.y = i;
					}
					if(d == sel.day && m == sel.month && y == sel.year)
					{
						fg = st.fgselect;
						bg = st.bgselect;
						fnt.Bold();
						special = true;

						prevday.x = j;
						prevday.y = i;
					}
					if (!WhenPaintDay.Empty()){              // <== Inserted line
						WhenPaintDay(Date(y,m,d),fg,bg); // <== Inserted line
					}                                        // <== Inserted line

				}
				else
				{
					fg = st.outofmonth;
					sd = d > 0 ? -d : d;
					Day(j, i) = sd;
				}

				if(sd == char(view.day))
				{
					if(sd < 0 && selall)
					{
						fg = st.outofmonth;
						fnt.Bold().Underline(!special);
					}
					if(sd > 0 && view.month == m)
					{
						fg = st.selectday;
						fnt.Bold().Underline(!special);
					}
				}
				if (!WhenPaintDay.Empty()){             // <== Inserted line
					WhenPaintDay(Date(y,m,d),fg,bg); 	// <== Inserted line
				}                                       // <== Inserted line

				w.DrawRect(xp, yp, cw, rh, bg);
				if(special)
				{
					DrawFrame(w, xp + 1, yp + 1, cw - 2, rh - 2, Black);
					DrawFrame(w, xp, yp, cw, rh, st.bgmain);
				}

				str = AsString(abs(d));
				w.DrawText(xp + (cw - GetTextSize(str, fnt).cx) / 2, yp + yc , str, fnt, fg);
			}

...
if(m == view.month)
{
	Day(j, i) = d;

	fg = Black;  // Shouldn't it be st.fgmain, instead??

	if(j == 6)
	{
		fg = Red; // Looks like there's no style color for this
	}
...

String curdate;

curdate = Format("%s %d", MonthName(view.month - 1), view.year);

	Calendar::Style& st = cal.StyleDefault().Write();
	st.font = Arial(8);
	st.bgmain = Color(33, 33, 33);
	st.bgselect = Color(190, 150, 80);
	st.bgtoday = Color(66, 66, 66);
	st.fgmain = Color(198, 198, 198);
	st.dayname = Color(190, 150, 80);
	st.fgselect = Color(198, 198, 198);
	st.selectday = Color(198, 198, 198);
	st.selecttoday = Color(190, 150, 80);
	st.today = Color(198, 198, 198);
	st.curdate = Color(198, 198, 198);
	st.cursorday = Color(255, 255, 192);
	st.fgtoday = Color(198, 198, 198);
	st.week = Color(127, 127, 127);
	st.header = Color(255, 127, 0);
	
	cal.SetStyle(Calendar::StyleDefault());
        cal.OneButton();

Calendar& Calendar::SetStyle(const Style& s)
{
	style = &s;
	nbg = Colorize(CtrlImg::Bg(), s.header, 150);
	spin_month.SetFont(s.font);  // inserted line
	spin_year.SetFont(s.font);   // inserted line
	spin_all.SetFont(s.font);    // inserted line
	UpdateFields();              // inserted line
	Refresh();
	return *this;
}

// Add new member Color weekend to Calendar Style definition:
class Calendar : public PopUpCtrl
{
public:
	struct Style : ChStyle<Style> {
		Color header;

		Color bgmain;
		Color bgtoday;
		Color bgselect;

		Color fgmain;
		Color fgtoday;
		Color fgselect;
		Color outofmonth;
		Color curdate;
		Color today;
		Color selecttoday;
		Color cursorday;
		Color selectday;
		Color line;
		Color dayname;
		Color week;
		Color weekend;				// <== Inserted line
		Font  font;
		Image spinleftimg;
		Image spinrightimg;
		bool  spinhighlight;
	};
...

...
if(m == view.month)
{
	Day(j, i) = d;

	fg = st.fgmain;	// fg = Black;			// <== Modified line

	if(j == 6)
	{
		fg = st.weekend; // fg = Red;		// <== Modified line
	}

...