DataSet is not allowing to bind a DataTable to a BindingSource

I have a problem, I am working on a project that uses DataSet, for a while I used to add DataTable in the DataSet and everything worked perfect. But recently I do all that I am supposed to do: -Open the DataSet designer, add a datable using the wizzard, (I choose table from database).. Click on "Build" everything goes fine. -Then in my winform I add a DataSet control, I choose the DataSet I want to work with(That one I added the datatable), then add BindingSource control, go to properties choose the datasource(DataSet I just added).. and here is the proble when I try to set up the DataMember ..the DataTable I just added is not listed.. .. I don't have any idea why..

So the temporal solution was create a new DataSet file and do all that proccess and with this new dataset it worked perfectly. But this situation came back with this new dataset, so again it seems that the datamember list is not updated, even though I always build the project.

Why is this happening ?