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
if ( pos > -1 )
		{
			bindingHandle = (ComputedColumnHandle) ( (ReportItemHandle) DEUtil.getBindingHolder( inputElement ) ).getColumnBindings( )
					.getAt( pos );
		}
		if ( bindingHandle == null )
			return;
		DataColumnBindingDialog dialog = new DataColumnBindingDialog( );
		dialog.setInput( (ReportItemHandle) inputElement, bindingHandle );
		dialog.setExpressionProvider( expressionProvider );
		if ( dialog.open( ) == Dialog.OK )
		{
			if ( bindingTable != null )
				bindingTable.getTable( ).setSelection( pos );
		}
	}
	protected void handleDelEvent( )
	{
		int pos = bindingTable.getTable( ).getSelectionIndex( );
		if ( pos > -1 )
		{
			try
			{
				ComputedColumnHandle handle = (ComputedColumnHandle) ( DEUtil.getBindingHolder( inputElement ) ).getColumnBindings( )
						.getAt( pos );
				deleteRow( handle );
			}
			catch ( Exception e1 )
			{
				ExceptionHandler.handle( e1 );