I was testing from commit be50469217bd775c4305938634c32e5932f47841 and noticed that the "out of sync" overlay went away correctly after mining blocks, but then after restarting with --reindex this black bar shows up after the overlay is hidden. I've only tested this in regtest mode. I'm not sure that the issue is related to the overlay but it seems to show up right when the overlay is hidden. 

![Screenshot_20191026_171200](https://user-images.githubusercontent.com/8107318/67627655-16153100-f815-11e9-967a-d5ea0a254965.png)


On another system:


Before reindex
![Screenshot_20191026_174635](https://user-images.githubusercontent.com/8107318/67627854-3515c200-f819-11e9-87b2-c6f8172480fd.png)


After reindex 
![Screenshot_20191026_174657](https://user-images.githubusercontent.com/8107318/67627855-38a94900-f819-11e9-87c1-c5296c1a2636.png)

int est_headers_left = bestHeaderDate.secsTo(QDateTime::currentDateTime()) / Params().GetConsensus().nPowTargetSpacing;
    ui->numberOfBlocksLeft->setText(tr("Unknown. Syncing Headers (%1, %2%)...").arg(bestHeaderHeight).arg(QString::number(100.0 / (bestHeaderHeight + est_headers_left) * bestHeaderHeight, 'f', 1)));
}
void ModalOverlay::toggleVisibility()
{
    showHide(layerIsVisible, true);
    if (!layerIsVisible)
        userClosed = true;
}
void ModalOverlay::showHide(bool hide, bool userRequested)
{
    if ( (layerIsVisible && !hide) || (!layerIsVisible && hide) || (!hide && userClosed && !userRequested))
        return;
    if (!isVisible() && !hide)
        setVisible(true);
    setGeometry(0, hide ? 0 : height(), width(), height());
    QPropertyAnimation* animation = new QPropertyAnimation(this, "pos");
    animation->setDuration(300);
    animation->setStartValue(QPoint(0, hide ? 0 : this->height()));
    animation->setEndValue(QPoint(0, hide ? this->height() : 0));
    animation->setEasingCurve(QEasingCurve::OutQuad);
    animation->start(QAbstractAnimation::DeleteWhenStopped);
    layerIsVisible = !hide;
}
void ModalOverlay::closeClicked()
{
    showHide(true);
    userClosed = true;
}