I am not able to resize the table widget column to it's contents

Hi,
I have created one QWidget which contains one QTableWidget having 3 columns.
The last column is "Description". I want the description column to expand depending on the length of the description provided by the user.
I tried to use
TableWidget->resizeColumnsToContents();
TableWidget->setWordWrap(true);

but still the texts are truncated or scrolled.
But one thing I observed, when i click on the header of the table then one very small triangle icon is coming on the header and the row is resizing to fit the contents.

Please provide me some inputs how can I fix this problem. I want it should automatically re-size the column, not user will have to click on the header.

please.........please..........