addButton/addSeparator: position argument


I am not sure about the usage of the position argument in addButton/addSeparator (v4.0.1), e.g.: if all items of a toolbar are in order 1,2,3…,n within the JS code, everything is working fine but as soon as the items are not in this exact order within the code, the buttons/separators are not displayed as expected by the position argument. Hence, what’s the purpose of the position argument?

    var assoc_menu = assoc_tabbar.tabs('tab_1').attachToolbar();
assoc_menu.addSeparator ('s1', 2);	
assoc_menu.addButton ('b2', 3, 'save');	
assoc_menu.addSeparator ('s2', 4);	
assoc_menu.addSeparator ('s3', 6);			
assoc_menu.addSeparator ('s4', 8);			
assoc_menu.addButton ('b5', 9, 'delete');	
assoc_menu.addSeparator ('s5', 10);		
assoc_menu.addButton ('b1', 1, 'new');
assoc_menu.addButton ('b4', 7, 'import');	
assoc_menu.addButton ('b3', 5, 'export');	

Many thanks.


already added items also have some index