I've gone through the older threads about this subject but didn't find anything regarding my problem at hand:

So I'm creating a QTableWidget which has some of its columns using a custom delegate which returns a QComboBox editor. My problem is that I cannot get it to work in all situations.

For example, I have my own ExcelDlg Dialog and in its constructor I create a QTableWidget and set it to using my delegate.

Like this:
Qt Code: 
  1. QStringList values;
  2.     values
  3.        << "DESC"
  4.        << "POS"
  5.        << "ABNORMAL INTERRUPTION"
  6.        << "TESTI VAAN"
  7.        << "VIELÄ YKS";
  8.  
  9.    cDropdownTableWidgetItemDelegate delegate;
  10.    delegate.setValues(values);
  11.  
  12.    QTableWidget *table = new QTableWidget(2,3,this);
  13.    table->setItemDelegate(&delegate);
  14.  
  15.    lo = new QHBoxLayout();   
  16.    lo->addWidget(table);
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Unfortunately the result is an empty table, no cells of any kind, only horizontal and vertical header items are displayed correctly.

But when I use it in a newly created dialog, for example:
Qt Code: 
  1. QStringList values;
  2.    values
  3.        << "DESC"
  4.        << "POS"
  5.        << "ABNORMAL INTERRUPTION"
  6.        << "TESTI VAAN"
  7.        << "VIELÄ YKS";
  8.  
  9.    cDropdownTableWidgetItemDelegate delegate;
  10.    delegate.setValues(values);
  11.  
  12.    QDialog *dlg = new QDialog();
  13.  
  14.    QTableWidget *table = new QTableWidget(2,3,dlg);   
  15.    table->setItemDelegate(&delegate);
  16.  
  17.    dlg->exec();
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It works fine. What is happening? Why is it not working in the upper example?

If needed, i can post the code to my delegate.