how to create tooltip for highlighted strings in QPlainTextEdit

I have a QPlainTextEdit and have some words highlighted in it. Now, when I hover over it with the mouse, I want it to show me a tooltip that has a description or something like that about this highlighted word. Something like this in the Qt IDE:

but I don't know how to start this so any idea, code or similar project to check would be helpful.

For this case I will create a class that inherits from QPlainTextEdit, reimplement the event() method and enable mouse tracking with setMouseTracking()

plaintextedit.h

#ifndef PLAINTEXTEDIT_H
#define PLAINTEXTEDIT_H

#include <QPlainTextEdit>

class PlainTextEdit : public QPlainTextEdit
{
public:
    PlainTextEdit(QWidget *parent=0);

    bool event(QEvent *event);
};

#endif // PLAINTEXTEDIT_H

plaintextedit.cpp

#include "plaintextedit.h"
#include <QToolTip>


PlainTextEdit::PlainTextEdit(QWidget *parent):QPlainTextEdit(parent)
{
    setMouseTracking(true);
}

bool PlainTextEdit::event(QEvent *event)
{
    if (event->type() == QEvent::ToolTip)
    {
        QHelpEvent* helpEvent = static_cast<QHelpEvent*>(event);
        QTextCursor cursor = cursorForPosition(helpEvent->pos());
        cursor.select(QTextCursor::WordUnderCursor);
        if (!cursor.selectedText().isEmpty())
            QToolTip::showText(helpEvent->globalPos(), /*your text*/QString("%1 %2").arg(cursor.selectedText()).arg(cursor.selectedText().length()) );

        else
            QToolTip::hideText();
        return true;
    }
    return QPlainTextEdit::event(event);
}

Complete Code: Here