[BeckyEbook]

I did a trial and raise() seems sufficient.
It doesn't need to be added to the Code View, as no other widgets can be added to this window.

void MainWindow::FocusOnBookBrowser()
{
    FocusOn(m_BookBrowser);
    m_BookBrowser->FocusOnBookBrowser();
    m_BookBrowser->raise();
    ShowMessageOnStatusBar(tr("Focus changed to BookBrowser window."));
}

void MainWindow::FocusOnPreview()
{
    FocusOn(m_PreviewWindow);
    m_PreviewWindow->SetFocusOnPreview();
    m_PreviewWindow->raise();
    ShowMessageOnStatusBar(tr("Focus changed to Preview window."));
}

void MainWindow::FocusOnTOC()
{
    FocusOn(m_TableOfContents);
    m_TableOfContents->SetFocusOnTOC();
    m_TableOfContents->raise();
    ShowMessageOnStatusBar(tr("Focus changed to Table Of Contents window."));
}

void MainWindow::FocusOnClips()
{
    FocusOn(m_Clips);
    m_Clips->SetFocusOnClips();
    m_Clips->raise();
    ShowMessageOnStatusBar(tr("Focus changed to Clips window."));
}