Hello PPL!
I have just started chapter 9, and wanted to play around so i added a new web form called defualt2.aspx, lang is c# and i selected the masterpage(only 1 masterpage exist) for that new web form, so its actually a content page.
without editing the page, i chose to 'view in browser', and the page came fine in Monochrome theme.

But when tried to change theme, i could saw that a post back occurs, but the theme will not change.
By going to the home page, I got the wellcome page, and there it all worked fine, and themes changed well.

I don't get it, and i think it has to do with the web.config file.
there is the following line there: I tried to remove the theme attribute but then the the browser brought a page with the following error in the browser:
""""""""""""""
Object reference not set to an instance of an object.
Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code.

Exception Details: System.NullReferenceException: Object reference not set to an instance of an object.

""""""""""""""
Any one has a clue what am i doing wrong?

thank u guys for any answer!

Well, i found the problem.
I've decided not to delete my message, if any one else has the same problem.
Here is the solution:
I reinstalled VS2010,and as a result, did not find the automatic way of adding web forms that already contains the next line in their code behind file:
public partial class Default2 : BasePage

instead, the original line showed which is:
public partial class Default2 : System.Web.UI.Page

So, it should be :public partial class Default2 : BasePage.

Good day 2 u all!