unable to edit the settings.

Hi...i am new to Nopcommerce.
i am working with nopcommerce 1.9.
when i edit or add new data like.....categories, product, or change themes in global settings....they don't change.
when i do this by running the site through visual studio...its working properly....
what is the problem ?......could anybody help me please.....

When you edit, do you save it each time? If not you need to.