Noticed this while reviewing #13529, but it's also in master @ 5ba77df. On macOS 10.13.6:

<img width="209" alt="schermafbeelding 2018-08-01 om 16 22 09" src="https://user-images.githubusercontent.com/10217/43527498-0f571db4-95a7-11e8-8d90-7863947a7689.png">


<img width="178" alt="schermafbeelding 2018-08-01 om 16 12 51" src="https://user-images.githubusercontent.com/10217/43526994-c9a515ec-95a5-11e8-96b8-9e2513e9aac5.png">

* `Show` in the action menu doesn't work if the app was hidden by `Command + H`, it does work when hidden through this menu
* send and receive don't unhide the window when opened for the action menu. It does navigate to the right tab. The other actions do work (sign, verify & debug window)

Clicking "Toon" (= macOS native show) does work, suggesting the GUI uses some non-native method of hiding.
while(font_size >= minPointSize) {
        font.setPointSizeF(font_size);
        QFontMetrics fm(font);
        if (fm.width(text) < width) {
            break;
        }
        font_size -= 0.5;
    }
    return font_size;
}
void ClickableLabel::mouseReleaseEvent(QMouseEvent *event)
{
    Q_EMIT clicked(event->pos());
}
void ClickableProgressBar::mouseReleaseEvent(QMouseEvent *event)
{
    Q_EMIT clicked(event->pos());
}
bool ItemDelegate::eventFilter(QObject *object, QEvent *event)
{
    if (event->type() == QEvent::KeyPress) {
        if (static_cast<QKeyEvent*>(event)->key() == Qt::Key_Escape) {
            Q_EMIT keyEscapePressed();
        }
    }
    return QItemDelegate::eventFilter(object, event);
}
}