QPlainTextEdit highlight selected line

Hi,

I'm trying to write simple debugger. I'd like to highlight current line when stepping over.
With help of code editor example I was able to do it like this:

Code:

---

void MainWindow::StepOver_cmd(void)
{
 
   QTextCursor cursor      =  dissasembly_widget->textCursor();
 
   cursor.movePosition(QTextCursor::Down,  QTextCursor::MoveAnchor);
   dissasembly_widget->setTextCursor(cursor);
 
   QList<QTextEdit::ExtraSelection> extraSelections;
   QTextEdit::ExtraSelection selection;
   QColor lineColor = QColor(Qt::cyan).darker(200);
   selection.format.setBackground(lineColor);
   selection.format.setProperty(QTextFormat::FullWidthSelection, true);
   selection.cursor = cursor;
 
   selection.cursor.clearSelection();
   extraSelections.append(selection);
   dissasembly_widget->setExtraSelections(extraSelections);
 
}

---

but the problem is when user changes cursor position it obviously starts to highlight code in different place.
The problem is with

dissasembly_widget->textCursor(); //dissasembly_widget is QPlainTextEdit

but I dont know how to do it otherwise since there is no setBlock function.
Thanks in advance!