Bob,

>The BindingSourceMember property will not stick in any textbox or checkbox on my form. As soon as I close the solution and open it again, the BindingSourceMember is blank again everywhere.
>
>Any ideas as to what can cause this?

After you set the property, switch to the HTML view of the page and verify that the IDE updated the HTML properly. Sometimes the IDE does not update the HTML properly. I've seen this behavior before and have had to enter property settings manually in the HTML. It seems that after doing that, the problem goes away.

I think that it's a bug in the IDE, but can't say for sure.