Subclassing QToolBox

[whitefurrows]

Hello,

i want to expand more than one page form a QToolBox. To do that i try to overwrite QToolBox::setCurrentIndex(int index). It works, but the problem is to use the following code form the original ToolBox within my subclass:

Q_D(QToolBox);
    QToolBoxPrivate::Page *c = d->page(index);
    if (!c || d->currentPage == c)
        return;

Q_D(QToolBox);
    QToolBoxPrivate::Page *c = d->page(index);
    if (!c || d->currentPage == c)
        return;

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The compiler output is: incomplete type 'QToolBoxPrivate' used in nested name specifier...

I don't understand how can i use the D-Pointer to access d->currentPage. Can you help me please?