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/ParameterDialog.java
String displayText = controlTypeChooser.getText( );
		if ( StringUtil.isBlank( displayText ) )
		{
			return getInputControlType( );
		}
		if ( DISPLAY_NAME_CONTROL_COMBO.equals( displayText ) )
		{
			return PARAM_CONTROL_COMBO;
		}
		if ( DISPLAY_NAME_CONTROL_LIST.equals( displayText ) )
		{
			return PARAM_CONTROL_LIST;
		}
		return CONTROL_TYPE_CHOICE_SET.findChoiceByDisplayName( displayText )
				.getName( );
	}
	private void changeDataType( )
	{
		String type = getSelectedDataType( );
		if ( type.equals( lastDataType ) )
		{
			return;
		}
		if ( buildControlTypeList( type ) )
		{
			changeControlType( );
		}
		lastDataType = type;
		if ( type.equals( DesignChoiceConstants.PARAM_TYPE_STRING ) )
		{