Bug 177439 Need an easy way to determine default value for a dynamic parameter
Currently, I have to bring up the data set editor, preview the results in the data set and make a mental note of the value to use for a report parameter that depends on a data set. It would be nice to have a drop down on the default value field, such as <Select value> which when selected queries the data set and presents me with a list to select from.
UI/org.eclipse.birt.report.designer.ui/src/org/eclipse/birt/report/designer/ui/dialogs/CascadingParametersDialog.java
{
			displayTypeChooser.clearSelection( ); 
		}
		else
		{
			displayTypeChooser.setText( getInputDisplayName( ) );
		}
		defaultValue = selectedParameter.getDefaultValue( );
		if ( getSelectedDataType( ).equals( DesignChoiceConstants.PARAM_TYPE_STRING ) )
		{
			if ( defaultValue == null )
			{
				defaultValueChooser.setText( CHOICE_NULL_VALUE );
			}
			else if ( defaultValue.equals( "" ) )
			{
				defaultValueChooser.setText( CHOICE_BLANK_VALUE );
			}
			else
			{
				defaultValueChooser.setText( defaultValue );
			}
		}
		else
		{
			if ( defaultValue == null )
			{
				defaultValueChooser.setText( "" ); 			
			}
			else