change config on combo at runtime

[namrms]

Hi,
I would like to keep a combo box component non editable initially(at this point the store is not loaded), Make it editable only on load of the corresponding store.

How do I change the config on the fly ?
Using extJS version 4

Regards,
Namratha

[namrms]

I am aware of the setEditable(boolean) method , However I am looking I want to have the config as described below :

1)when combo store is empty : editable : false,typeAhead:false,selectOnFocus : false
2)when combo store is loaded : editable : true,typeAhead:true,selectOnFocus : true

so basically how to change the type ahead and selectOnFocus configs..?