Question: I have never worked with VBA, therefore this could by an easy task, but I can't get it working :-) Simply I need to catch a run time error in following code : 

```
Private Sub CheckBox1_Click()

ActiveWorkbook.Sheets("(X)").Unprotect
ActiveWorkbook.Sheets("(X)").Select
ActiveSheet.Range("F18").Select
'here comes the error
ActiveSheet.Range("$A$2:$X$310").AutoFilter Field:=1, Criteria1:="1"
Sheets("(40 UKÁŽKA)").Protect DrawingObjects:=True, Contents:=True, Scenarios:=True
End Sub

```

Answer: 
Look into the concept of [ViewStack navigation containers](http://help.adobe.com/en_US/flex/using/WS2db454920e96a9e51e63e3d11c0bf69084-7e4d.html), which handles pretty much what you want. You could also use [PopUpManager](http://help.adobe.com/en_US/FlashPlatform/reference/actionscript/3/mx/managers/PopUpManager.html) to pop it open depending on your feeds.mxml class.
The cleanest way is usually to use a ViewStack. Depending on your requirements you may also be interested in using a TabNavigator or just a custom component as the "authenticatedView" of your primary ViewStack.

Fx 3 example:

```
    <mx:ViewStack id="viewStack">

        <mx:Canvas id="nonAuthenticatedView"/>
            //Your login screen "stuff" can go here.
            //On a successful login: viewStack.selectedIndex = 1.
            //On logout set selectedIndex to 0 to return to the login screen.
        </mx:Canvas>

        <mx:Canvas id="authenticatedView">
            //Instead of a Canvas this could be whatever, another ViewStack, TabNavigator, custom component, etc.
        </mx:Canvas>

    </mx:ViewStack>

```

This can get a lot more sophisticated if you start using a singleton model, bindings, and so on, but this should get you started.