DataGrid and TextBox binding problem....

Question

Hi, i have one simple form with an horizontal spliter. in the top of the spliter i have 1 tab control with two pages, 1 datagridview on tabpage 1 binded to customers dataset and one textbox on tabpage 2 binded to customers name (same dataset). On the bottom of the splitter i have a binding navigator, binded to customers binding source, though working with both tabpages.
finally, i have a button on the bottom with this click event:
MessageBox.Show(bDDataSet.HasChanges().ToString());

when i make any changes in the first tabpage and i click the botton the answer is true, dataset has changes.

my problem is, when i make any changes to the name field in the textbox on tabpage2, the answer is that i don't have any changes in the data set. i change to tabpage one and in the same focused row i notice that the field name has the changes i made on tabpage 2. i click again but still the answer is no. I change focus to the next row on the grid, i click and the answer is yes!!!

my question is how can i get a dataset.haschanges()=true just changing data in my textbox?

any help will be deeply appreciated.

thanks in advance!