In Ext.Fx class documentation at afterStyle config there are the information:

afterStyle : String/Object/Function
A style specification string, e.g. "width:100px", or an object in the form {width:"100px"}, or a function which returns such a specification that will be applied to the Element after the effect finishes.

But when use the string specification (for example: "width:100px") the style don't change. I checked the code
of Ext.Fx and of setStyle method in Ext.Element and I verified that this
option realy don't work in this way.