Combo Box Help - can't solve

Question

Using VS 2003 Database: Access When I select (bind) the proper DataSource (e.g. DataSet.table) and DisplayMember (a table column) in the property window of VS for a combo box (CB) does anyone know why when I run the local application clicking on the CB control doesn't reveal the actual drop down box (i.e. values). However, if I select a different table in that same DataSet (DS) the CB works fine. Note: that second DS.table is used in the datagrid on that same form. I have done everything (previewed data, schema, keys, new DS, etc). HINT maybe?: the first mouse click on the CB arrow down buton depresses the arrow down button. HOWEVER, the next click on the button or, anywhere on the entire form, does nothing. Focus problem?