Bug 118644 Hint for Date Time Parameters
The hint you give for date time parameters (Please enter date ... pattern: MM/DD/YYYY ....) is only true if the date is unformatted. If you apply a format, you must enter it according to it. So it's quite confusing!
UI/org.eclipse.birt.report.designer.ui/src/org/eclipse/birt/report/designer/ui/dialogs/ParameterDialog.java
{
				if ( isDefaultChoice( choice ) )
				{
					text = FLAG_DEFAULT;
				}
			}
			else if ( columnIndex == valueIndex )
			{
				if ( choice == dummyChoice )
				{
					text = INPUT_PROPMT;
				}
				else
				{
					text = format( choice.getValue( ) );
				}
			}
			else if ( columnIndex == valueIndex + 1 )
			{
				text = choice.getLabel( );
			}
			if ( text == null )
			{
				text = ""; 
			}
			return text;
		}
		public void addListener( ILabelProviderListener listener )
		{
		}