User Portlet User Portlet

Usually we define a function with default values by the syntax x_:default, but there is another technique to do this by registering a global default value with Default. In the Document, there are three ways to use Default, two of...
I've tried your code and your issue doesn't occur in my Mathematica v9.01, Win 7 OS.
What have you done about your question? Why not try it yourself by using the Writing Assistant?