Bug 161219 Gantt chart with null datapoints fail to render
Create a dataset with two date columns, having some null date values Create a gantt chart Assign the dates to the gant series It fails to render and throw exception. Expected: null dates should be treated as: - 1 null date, 1 valid date ->one marker drawn, no line - 2 null dates -> skip rendering of datapoint If the decoration label is missing it should also not fail.
chart/org.eclipse.birt.chart.engine/src/org/eclipse/birt/chart/util/CDateTime.java
}
		else if ( iUnit == Calendar.SECOND )
		{
			double rt = ( l1 - l2 ) / MILLIS_IN_SECOND;
			if ( trimBelow )
			{
				rt = Math.floor( rt );
			}
			return rt;
		}
		else if ( iUnit == Calendar.MINUTE )
		{
			double rt = ( l1 - l2 ) / MILLIS_IN_MINUTE;
			if ( trimBelow )
			{
				rt = Math.floor( rt );
			}
			return rt;
		}
		else if ( iUnit == Calendar.HOUR_OF_DAY )
		{
			double rt = ( l1 - l2 ) / MILLIS_IN_HOUR;
			if ( trimBelow )
			{
				rt = Math.floor( rt );
			}
			return rt;
		}
		else if ( iUnit == Calendar.DATE )
		{