cannot create tablebox and reload data programmaticaly

[#1]

I have created empty qvw document with one sheet "Main" and with loading data script:
"... SQL Execute test_procedure1; ". Test_procedure1 returns a result set with one column "col1".

Now I'm trying to create a tableBox with one column:
TableBox table = app.ActiveDocument().ActivateSheet("Main").CreateTableBox();
table.AddField("col1");
app.ActiveDocument().DoReload(1, false, false);


I can see only the toolbar (with "Print", "Send to excel", "Minimize" and "Maximize"). No column header, no data rows.

But when I open Table Box Properties Dialog and manually remove and add col1 to "Fields Displayed in Tablebox" - it works.
What is the problem?