By default, the BackColorChart property is 0. The property has no effect if it is 0. The BackColorChart property controls the background of the time scale unit being shown in the chart. Use the DrawGridLines property to specify whether the grid lines are shown in the time unit in the chart area.  The BackColor property controls the background of the time scale unit being shown in the chart's header. The PatternChart property specifies the pattern to show on the chart.

Use the BackColorChart property to change the visual appearance for a time unit,  in the chart as in the following screen shot ( in red ):

 

The following VB sample shows how can I change the background color for a time unit, in the chart area:

With G2antt1
	.BeginUpdate 
	With .Chart
		.LevelCount = 2
		.FirstVisibleDate = #1/1/2008#
		.AllowInsideZoom = True
		.AllowResizeInsideZoom = False
		.InsideZoomOnDblClick = False
		.DefaultInsideZoomFormat.BackColorChart = 255
		With .InsideZooms
			.SplitBaseLevel = False
			.DefaultWidth = 18
			.Add(#1/4/2008#).AllowInsideFormat = False
		End With
	End With
	.EndUpdate 
End With

The following VB.NET sample shows how can I change the background color for a time unit, in the chart area:

With AxG2antt1
	.BeginUpdate 
	With .Chart
		.LevelCount = 2
		.FirstVisibleDate = #1/1/2008#
		.AllowInsideZoom = True
		.AllowResizeInsideZoom = False
		.InsideZoomOnDblClick = False
		.DefaultInsideZoomFormat.BackColorChart = 255
		With .InsideZooms
			.SplitBaseLevel = False
			.DefaultWidth = 18
			.Add(#1/4/2008#).AllowInsideFormat = False
		End With
	End With
	.EndUpdate 
End With

The following C++ sample shows how can I change the background color for a time unit, in the chart area:

/*
	Copy and paste the following directives to your header file as
	it defines the namespace 'EXG2ANTTLib' for the library: 'ExG2antt 1.0 Control Library'

	#import <ExG2antt.dll>
	using namespace EXG2ANTTLib;
*/
EXG2ANTTLib::IG2anttPtr spG2antt1 = GetDlgItem(IDC_G2ANTT1)->GetControlUnknown();
spG2antt1->BeginUpdate();
EXG2ANTTLib::IChartPtr var_Chart = spG2antt1->GetChart();
	var_Chart->PutLevelCount(2);
	var_Chart->PutFirstVisibleDate("1/1/2008");
	var_Chart->PutAllowInsideZoom(VARIANT_TRUE);
	var_Chart->PutAllowResizeInsideZoom(VARIANT_FALSE);
	var_Chart->PutInsideZoomOnDblClick(VARIANT_FALSE);
	var_Chart->GetDefaultInsideZoomFormat()->PutBackColorChart(255);
	EXG2ANTTLib::IInsideZoomsPtr var_InsideZooms = var_Chart->GetInsideZooms();
		var_InsideZooms->PutSplitBaseLevel(VARIANT_FALSE);
		var_InsideZooms->PutDefaultWidth(18);
		var_InsideZooms->Add("1/4/2008")->PutAllowInsideFormat(VARIANT_FALSE);
spG2antt1->EndUpdate();

The following C# sample shows how can I change the background color for a time unit, in the chart area:

axG2antt1.BeginUpdate();
EXG2ANTTLib.Chart var_Chart = axG2antt1.Chart;
	var_Chart.LevelCount = 2;
	var_Chart.FirstVisibleDate = "1/1/2008";
	var_Chart.AllowInsideZoom = true;
	var_Chart.AllowResizeInsideZoom = false;
	var_Chart.InsideZoomOnDblClick = false;
	var_Chart.DefaultInsideZoomFormat.BackColorChart = 255;
	EXG2ANTTLib.InsideZooms var_InsideZooms = var_Chart.InsideZooms;
		var_InsideZooms.SplitBaseLevel = false;
		var_InsideZooms.DefaultWidth = 18;
		var_InsideZooms.Add("1/4/2008").AllowInsideFormat = false;
axG2antt1.EndUpdate();

The following VFP sample shows how can I change the background color for a time unit, in the chart area:

with thisform.G2antt1
	.BeginUpdate
	with .Chart
		.LevelCount = 2
		.FirstVisibleDate = {^2008-1-1}
		.AllowInsideZoom = .T.
		.AllowResizeInsideZoom = .F.
		.InsideZoomOnDblClick = .F.
		.DefaultInsideZoomFormat.BackColorChart = 255
		with .InsideZooms
			.SplitBaseLevel = .F.
			.DefaultWidth = 18
			.Add({^2008-1-4}).AllowInsideFormat = .F.
		endwith
	endwith
	.EndUpdate
endwith