extjs - What is the syntax to add a panel to a viewport component? -

from examples have found, code should add newpanel viewport east region, nothing:

var viewport = new ext.viewport({     layout: 'border',     items: [ regionmenu, regioncontent ] });  var newpanel = new ext.panel({     region: 'east',     width: 300,     html: 'this panel added' }); viewport.add(newpanel); 

how can add new panel viewport?

addendum

i got work, here main code same issue, i'm not adding viewport region within viewport, , empty region of contents before add new contents:

ext.onready(function(){      ...      regioncontent = new ext.panel({         id: 'contentarea',         region: 'center',         padding:'10',         autoscroll: true     });      var viewport = new ext.viewport({         layout: 'border',         items: [ regionmenu, regioncontent ]     });      clearextjscomponent(regioncontent);     var start_info_panel = new ext.panel({         title: 'start info',         padding: 10,         width: 300,         html: 'this panel added start view'     });     regioncontent.add(start_info_panel);     regioncontent.dolayout();  });   function clearextjscomponent(cmp) {     var f;     while(f = cmp.items.first()){         cmp.remove(f, true);     } } 

you may need call viewport.dolayout() after add newpanel because viewport rendered:

viewport.add(newpanel); viewport.dolayout(); 

from add() documentation:

if container rendered when add called, may need call dolayout refresh view causes unrendered child components rendered. required can add multiple child components if needed while refreshing layout once.