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
};
		groups = new String[groupList.size( ) + 1];
		groups[0] = ALL;
		for ( int i = 0; i < groupList.size( ); i++ )
		{
			groups[i + 1] = ( (GroupHandle) groupList.get( i ) ).getName( );
		}
		cellEditors = new CellEditor[]{
				null,
				new TextCellEditor( table ),
				new ComboBoxCellEditor( table, dataTypeDisplayNames ),
				expressionCellEditor,
				new ComboBoxCellEditor( table, groups, SWT.READ_ONLY ),
		};
		for ( int i = 0; i < columns.length; i++ )
		{
			TableColumn column = new TableColumn( table, SWT.LEFT );
			column.setResizable( columns[i] != null );
			if ( columns[i] != null )
			{
				column.setText( columns[i] );
			}
			column.setWidth( columnWidth[i] );
		}
		if ( canSelect )
		{
			bindingTable = new CheckboxTableViewer( table );
			( (CheckboxTableViewer) bindingTable ).addCheckStateListener( new ICheckStateListener( ) {
				public void checkStateChanged( CheckStateChangedEvent event )
				{