Bug 155365 Can not set data type to "date time" when editing "Data Item"
Description: Can not set data type to "date time" when editing "Data Item" Steps to reproduce: 1. Insert a data item to the layout 2. Name it and set the expression to "a = new Date()" 3. Select the data type to date time 4. Press ok Actual result: An Birt Exception is thrown out. Expected result: No NPE thrown out
UI/org.eclipse.birt.report.designer.ui/src/org/eclipse/birt/report/designer/ui/dialogs/ColumnBindingDialog.java
String currentDataSetName = getDataSetName( );
		if ( currentDataSetName == null
				&& !inputElement.columnBindingsIterator( ).hasNext( ) )
		{
			return 0;
		}
		else if ( currentDataSetName == newName
				|| ( currentDataSetName != null && currentDataSetName.equals( newName ) ) )
		{
			return 2;
		}
		MessageDialog prefDialog = new MessageDialog( UIUtil.getDefaultShell( ),
				Messages.getString( "dataBinding.title.changeDataSet" ),
				null,
				Messages.getString( "dataBinding.message.changeDataSet" ),
				MessageDialog.INFORMATION,
				new String[]{
						IDialogConstants.YES_LABEL,
						IDialogConstants.NO_LABEL,
						IDialogConstants.CANCEL_LABEL,
				},
				0 );
		return prefDialog.open( );
	}
	private String getDataSetName( )
	{
		if ( inputElement.getDataSet( ) == null )
		{
			return null;
		}