Hi,
i have 2 tabs.
1 with a form and 1 with a grid.
Now with the grid there is no problem , but i have problems with the form.
Playin arround with layoutontabchange and deferredrender i can manage that the form will show up again , but it will also show up on the other tab!

this happens when i close the tabs and open them again.


Code:
 xtype:'tabpanel',
            activeTab:0,
            region:'center',
            margins:'90 5 5 0',
            deferredRender: true,
layoutOnTabChange: true,
autoDestroy:false,
//forceLayout: true,
            //autoHeight:true,
            //resizable:true,
            id:'apptabs',

my code for the links
Code:
/*
 *  The supplier menu items
 *  
 */
 
Ext.EventManager.addListener("supplier_tree", 'click', function(){
 
     var json2 = [
        {"text" : "Supplier Management", "id" : 100, "leaf" : false, "cls" : "folder", "children" : [
            {"text" : "add supplier", "id" : 1000, "leaf" : true, "cls" : "folder"
            },
            {"text" : "supplier overview", "id" : 2000, "leaf" : true, "cls" : "folder"
            },
        ]}
    ];    
    if (!Ext.get('static_supplier_menu')) {
        var tree2 = new Ext.tree.TreePanel({
            id:'static_supplier_menu',
            animate: true,
            enableDD: false,
            loader: new Ext.tree.TreeLoader(), // Note: no dataurl, register a TreeLoader to make use of createNode()
            lines: false,
            border:false,
            renderTo: 'supplier_tree_div',
            root: new Ext.tree.AsyncTreeNode({
                text: 'Suppliers',
                draggable: false,
                id: 'source',
                children: json2
            }),
            rootVisible: true,
        });
        tree2.on("click", function(node, e) {  
 
           switch (node.id)
           {
               /* add provider */
               case 1000:
            if (Ext.getCmp('apptabs').findById('number_management_id') &&
            Ext.getCmp('apptabs').findById('number_management_id').isVisible()) {
 
                    //Ext.getCmp('apptabs').setActiveTab('number_management_id');
               //     Ext.getCmp('apptabs').findById('number_management_id').doLayout();
                    return;
            }
            else {
 
                Ext.getCmp('apptabs').add({
                    layout: 'form',
                    resizable: true,
                    closable: true,
                    id: 'number_management_id',
                    title: 'Supplier management',
                    items: [saveSuppliers]
                });
                Ext.getCmp('apptabs').setActiveTab('number_management_id');
                //Ext.getCmp('apptabs').findById('number_management_id').load({url:"providers.php",scripts: true});
                Ext.getCmp('apptabs').findById('number_management_id').doLayout();
            }
            break;
            /* grid supplier */
            case 2000:
            if (Ext.getCmp('apptabs').findById('supplier_management_grid') &&
            Ext.getCmp('apptabs').findById('supplier_management_grid').isVisible()) {
                    //Ext.getCmp('apptabs').setActiveTab('supplier_management_grid');
                  //  Ext.getCmp('apptabs').findById('supplier_management_grid').doLayout();
                    return;
            }
            else {
 
                Ext.getCmp('apptabs').add({
                    layout: 'fit',
                    resizable: true,
                    closable: true,
                    id: 'supplier_management_grid',
                    title: 'Supplier overview',
                    items: new ProvidersGrid()
                });
                Ext.getCmp('apptabs').setActiveTab('supplier_management_grid');
                Ext.getCmp('apptabs').findById('supplier_management_grid').doLayout();
            }
            break;
 
 
           }
                          });
    }else return;
 
}, this, { preventDefault: true } );

with the current config , when having opened the tabs once and closed them and then opening them again ,it will show on both tabs the form .
I also get an error now and then with pokin around and it tells me:

Ext.fly(el) is null
[Break on this error]
Ext.fly(el).addClass('x-tab-strip-active');\r\n