hangup vertical scroll bar in qtextedit

[mero]

I've got textedit and i want display menu so i do:

void MainTextEdit::mousePressEvent(QMouseEvent *event)
{
    if (parent->isActiveWindow() == false) QTextEdit::mousePressEvent(event); // prevent bug
 
    if (event->button() == Qt::RightButton)
    {
        if (this->textCursor().selectedText().isEmpty() == true) // if nothing selected
        {
            QTextCursor cursor = cursorForPosition(event->pos());
            cursor.select(QTextCursor::WordUnderCursor);
            if (!cursor.selectedText().isEmpty())
            {
                QString strText = cursor.selectedText();
                int iPos = cursor.position() - cursor.block().position(); // cursor.positionInBlock()
 
                cursor.select(QTextCursor::BlockUnderCursor);
                QString strBlock = cursor.selectedText().trimmed();
                QStringList strlBlock = strBlock.split(" ");
 
                QString strWord = strlBlock[1];
 
                // channel
                if (strText.at(0) == '#')
                {
...
                    QMenu *menu = new QMenu(strChannel);
...
                    menu->popup(mapToGlobal(event->pos()));
                }
 
                // nick
                if ((iPos > 11) && (iPos < 11+2+strWord.length()))
                {
...
                        QMenu *menu = new QMenu(strNick);
...
                        menu->popup(mapToGlobal(event->pos()));
                    }
                }
            }
        }
    }
 
    QTextEdit::mousePressEvent(event);
}

void MainTextEdit::mousePressEvent(QMouseEvent *event)
{
    if (parent->isActiveWindow() == false) QTextEdit::mousePressEvent(event); // prevent bug

    if (event->button() == Qt::RightButton)
    {
        if (this->textCursor().selectedText().isEmpty() == true) // if nothing selected
        {
            QTextCursor cursor = cursorForPosition(event->pos());
            cursor.select(QTextCursor::WordUnderCursor);
            if (!cursor.selectedText().isEmpty())
            {
                QString strText = cursor.selectedText();
                int iPos = cursor.position() - cursor.block().position(); // cursor.positionInBlock()

                cursor.select(QTextCursor::BlockUnderCursor);
                QString strBlock = cursor.selectedText().trimmed();
                QStringList strlBlock = strBlock.split(" ");

                QString strWord = strlBlock[1];

                // channel
                if (strText.at(0) == '#')
                {
...
                    QMenu *menu = new QMenu(strChannel);
...
                    menu->popup(mapToGlobal(event->pos()));
                }

                // nick
                if ((iPos > 11) && (iPos < 11+2+strWord.length()))
                {
...
                        QMenu *menu = new QMenu(strNick);
...
                        menu->popup(mapToGlobal(event->pos()));
                    }
                }
            }
        }
    }

    QTextEdit::mousePressEvent(event);
}

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this code is working good but sometimes vertical scroll bar stops, and moving it to bottom by mouse don't work - because after adding next line of text it back to "saved"? position ...

maybe I forget to add something ?