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
&& groupType != DEUtil.TYPE_GROUP_NONE )
						{
							text = ALL;
						}
						else
							text = NONE_AGGREGATEON;
					}
					else
					{
						if ( groupType == DEUtil.TYPE_GROUP_NONE )
						{
							text = NONE_AGGREGATEON;
							handle.setAggregateOn( null );
						}
						else
							text = value;
					}
					break;
			}
			if ( text == null )
			{
				text = ""; 
			}
			return text;
		}
		public void addListener( ILabelProviderListener listener )
		{
		}
		public void dispose( )
		{