Bug 146796 Error message pop up if display text contain non-digital char when add next item
Description: In decimal type parameter creation,display type is "list box", Error message pop up if "display text" contain non-digital char when add next item. Steps: 1.Create a new decimal parameter 2.Set display type as "list box" 3.Input one item: value:1, display text:test 4.Input another item: Value:2 Actual result: error message pop up: The display text already exists! Expected result: Input item succussfully.
UI/org.eclipse.birt.report.designer.ui/src/org/eclipse/birt/report/designer/ui/dialogs/ParameterDialog.java
inputParameter.setValueType( DesignChoiceConstants.PARAM_VALUE_TYPE_STATIC );
				if ( !DesignChoiceConstants.PARAM_CONTROL_TEXT_BOX.equals( newControlType )
						&& !DesignChoiceConstants.PARAM_CONTROL_CHECK_BOX.equals( newControlType ) )
				{
					for ( Iterator iter = choiceList.iterator( ); iter.hasNext( ); )
					{
						SelectionChoice choice = (SelectionChoice) iter.next( );
						if ( isValidValue( choice.getValue( ) ) == null )
						{
							selectionChioceList.addItem( choice );
						}
					}
				}
				inputParameter.setDataSetName( null );
				inputParameter.setValueExpr( null );
				inputParameter.setLabelExpr( null );
			}
			else
			{
				
				inputParameter.setValueType( DesignChoiceConstants.PARAM_VALUE_TYPE_DYNAMIC );
				inputParameter.setDataSetName( dataSetChooser.getText( ) );
				inputParameter.setValueExpr( getExpression( columnChooser.getText( ) ) );
				inputParameter.setLabelExpr( getExpression( displayTextChooser.getText( ) ) );
			}
			
			inputParameter.setHelpText( UIUtil.convertToModelString( helpTextEditor.getText( ),
					false ) );