public FrmVisita()
 {
     InitializeComponent();
     this.Shown += FrmVisita_Shown;
     this.Activated += FrmVisita_Activated;
 }
 Size sizeNormal;
 private void FrmVisita_Activated(object? sender, EventArgs e)
 {
     if (this.WindowState == FormWindowState.Minimized)
     {
         this.WindowState = FormWindowState.Normal;
         this.Size = sizeNormal;
     }
 }

 private void FrmVisita_Shown(object? sender, EventArgs e)
 {
     sizeNormal = this.Size;
 }