OK, try to clear selected items before selecting by index:
switch (entities.ElementAt(0).TypeId)
{
case 1:
this.panLoads.Hidden = false;
cboTipo.SelectedItems.Clear();
cboCargas.SelectedItems.Clear();
this.cboTipo.SelectedItem.Index = 0;
if (entities.ElementAt(0).ResourceId > 2)
{
index = 2;
}
else
{
index = 0;
}
this.cboCargas.SelectedItem.Index = index;
this.cboCargas.UpdateSelectedItems();
break;
case 4:
this.panSql.Hidden = false;
this.cboTipo.SelectedItems.Clear();
this.cboConexion.SelectedItems.Clear();
this.cboTipo.SelectedItem.Index = 1;
this.txtSQL.Text = entities.ElementAt(0).Description;
if (entities.ElementAt(0).ResourceId > 2)
{
index = 3;
}
else
{
index = 1;
}
this.cboConexion.SelectedItem.Index = index;
this.cboConexion.UpdateSelectedItems();
break;
}