By default, the DefaultWidth property is 128 pixels. Changing the DefaultWidth property has no effect for already added inside zoom units. In this case, you can use the Width property to change the width for units. Use the AllowResize property to specify whether a specified unit is resizable. Use the CondInsideZoom property to specify a formula to define the time units that may be resized if the AllowResizeInsideZoom property is True. 

The following VB sample shows how can I change the label for a specified unit:

With G2antt1
	.BeginUpdate 
	With .Chart
		.PaneWidth(0) = 0
		.LevelCount = 2
		.FirstVisibleDate = #1/1/2008#
		.AllowInsideZoom = True
		.AllowResizeInsideZoom = False
		.InsideZoomOnDblClick = False
		.DefaultInsideZoomFormat.OwnerLabel = "<b><%d%></b> <%d2%>"
		With .InsideZooms
			.SplitBaseLevel = False
			.DefaultWidth = 32
			.Add(#1/4/2008#).AllowInsideFormat = False
		End With
	End With
	.EndUpdate 
End With

The following VB.NET sample shows how can I change the label for a specified unit:

With AxG2antt1
	.BeginUpdate 
	With .Chart
		.PaneWidth(0) = 0
		.LevelCount = 2
		.FirstVisibleDate = #1/1/2008#
		.AllowInsideZoom = True
		.AllowResizeInsideZoom = False
		.InsideZoomOnDblClick = False
		.DefaultInsideZoomFormat.OwnerLabel = "<b><%d%></b> <%d2%>"
		With .InsideZooms
			.SplitBaseLevel = False
			.DefaultWidth = 32
			.Add(#1/4/2008#).AllowInsideFormat = False
		End With
	End With
	.EndUpdate 
End With

The following C++ sample shows how can I change the label for a specified unit:

/*
	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->PutPaneWidth(0,0);
	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()->PutOwnerLabel(L"<b><%d%></b> <%d2%>");
	EXG2ANTTLib::IInsideZoomsPtr var_InsideZooms = var_Chart->GetInsideZooms();
		var_InsideZooms->PutSplitBaseLevel(VARIANT_FALSE);
		var_InsideZooms->PutDefaultWidth(32);
		var_InsideZooms->Add("1/4/2008")->PutAllowInsideFormat(VARIANT_FALSE);
spG2antt1->EndUpdate();

The following C# sample shows how can I change the label for a specified unit:

axG2antt1.BeginUpdate();
EXG2ANTTLib.Chart var_Chart = axG2antt1.Chart;
	var_Chart.set_PaneWidth(0 != 0,0);
	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.OwnerLabel = "<b><%d%></b> <%d2%>";
	EXG2ANTTLib.InsideZooms var_InsideZooms = var_Chart.InsideZooms;
		var_InsideZooms.SplitBaseLevel = false;
		var_InsideZooms.DefaultWidth = 32;
		var_InsideZooms.Add("1/4/2008").AllowInsideFormat = false;
axG2antt1.EndUpdate();

The following VFP sample shows how can I change the label for a specified unit:

with thisform.G2antt1
	.BeginUpdate
	with .Chart
		.PaneWidth(0) = 0
		.LevelCount = 2
		.FirstVisibleDate = {^2008-1-1}
		.AllowInsideZoom = .T.
		.AllowResizeInsideZoom = .F.
		.InsideZoomOnDblClick = .F.
		.DefaultInsideZoomFormat.OwnerLabel = "<b><%d%></b> <%d2%>"
		with .InsideZooms
			.SplitBaseLevel = .F.
			.DefaultWidth = 32
			.Add({^2008-1-4}).AllowInsideFormat = .F.
		endwith
	endwith
	.EndUpdate
endwith