Thank you for your support, but there is something in my code that breaks.
Here is an outline of code of what I am trying:

1) context:
- simple designer generated forms app.
- each form contains a DataGridView bound to a BindingSource that is bound
to a DataSet & Table, plus a BindingNavigator bound to the same BindingSource

2) creation of static dataset
In the project namespace, I added to the static class Program:
namespace GesDent
{
   static class Program
   {
       public static DataSetGesDent dataSetGesDent;
       public static
GesDent.DataSetGesDentTableAdapters.tblPatientsTableAdapter
tblPatientsTableAdapter;
       public static System.Windows.Forms.BindingSource
tblPatientsBindingSource;

       protected static void LoadDB()
       {
           dataSetGesDent = new DataSetGesDent();

           tblPatientsTableAdapter = new
GesDent.DataSetGesDentTableAdapters.tblPatientsTableAdapter();
           tblPatientsBindingSource = new
System.Windows.Forms.BindingSource();
           tblPatientsBindingSource.DataSource = tblPatientsTableAdapter;
           tblPatientsTableAdapter.ClearBeforeFill = true;
           tblPatientsTableAdapter.Fill(Program.dataSetGesDent.tblPatients);
       }

       public static void SaveDB()
       {
           tblPatientsBindingSource.EndEdit();
           
tblPatientsTableAdapter.Update(Program.dataSetGesDent.tblPatients);
       }

And then, in the Main function, I put a call to the LoadDb method:
       static void Main()
       {
           Application.EnableVisualStyles();
           Application.SetCompatibleTextRenderingDefault(false);
           LoadDB();
           Application.Run(new FormPatients());
       }

3) use of the data
a) If I put into the form’s constructor the static dataset stuff assignment
to the local dataset instance after InitializeComponent call, as you told me,
I cannot see any data in the grid:
namespace GesDent
{
   public partial class FormPatients : Form
   {
       public FormPatients()
       {
           InitializeComponent();
           this.dataSetGesDent = Program.dataSetGesDent;
           this.tblPatientsTableAdapter = Program.tblPatientsTableAdapter;
           this.tblPatientsBindingSource = Program.tblPatientsBindingSource;
       }

b) if I make the assignment into the designer generated InitializeComponent
method, just after the allocation code (that I have to leave, otherwise the
designer doesn’t recognize the form any more), everything will work:
       private void InitializeComponent()
       {
           this.components = new System.ComponentModel.Container();
           System.ComponentModel.ComponentResourceManager resources = new
System.ComponentModel.ComponentResourceManager(typeof(FormPatients));
           this.dataSetGesDent = new GesDent.DataSetGesDent();
           this.tblPatientsTableAdapter = new
GesDent.DataSetGesDentTableAdapters.tblPatientsTableAdapter();
           this.tblPatientsBindingSource = new
System.Windows.Forms.BindingSource(this.components);
           // section added by hand
           this.dataSetGesDent = Program.dataSetGesDent;
           this.tblPatientsTableAdapter = Program.tblPatientsTableAdapter;
           this.tblPatientsBindingSource = Program.tblPatientsBindingSource;
           // end section added by hand
           this.dataGridViewPatients = new
System.Windows.Forms.DataGridView();
        …..
What I am missing?
Thank you in advance for your help.

Flavio