Bug 190727 [regression]Default value issue when switch report parameter from textbox to listbox.[0705]
UI/org.eclipse.birt.report.designer.ui/src/org/eclipse/birt/report/designer/ui/dialogs/ParameterDialog.java
{
			for ( int i = 0; i < elements.length; i++ )
			{
				if ( isDefaultChoice( (SelectionChoice) elements[i] ) )
				{
					changeDefaultValue( null );
				}
				choiceList.remove( elements[i] );
			}
			return true;
		}
	};
	private Text listLimit;
	/**
	 * Create a new parameter dialog with given title under the active shell
	 * 
	 * @param title
	 *            the title of the dialog
	 */
	public ParameterDialog( String title )
	{
		this( UIUtil.getDefaultShell( ), title );
	}
	/**
	 * Create a new parameter dialog with given title under the specified shell
	 * 
	 * @param parentShell
	 *            the parent shell of the dialog
	 * @param title
	 *            the title of the dialog