_Second try - first issue got deleted suddenly..._

When confirming too big transactions, depending on screen resolution with each output the buttons move lower and lower until they are not visible anymore on the screen.

Additionally randomly after a couple transactions the client starts to repeat its content in the confirmation prompt making even the smalest 1:1 transaction unusable as the buttons are not visible, again. (See screenshot)

I (A) would expect that the buttons are visible no matter how big the transaction content is (for example by making the content scrollable) and (B) don't understand why the content is repeating suddenly.

Using Bitcoin Knots 17 but have been directed by the developers that the issue belongs to bitcoin/bitcoin

![bug-NEW](https://user-images.githubusercontent.com/48955884/55005357-2396de00-4fdc-11e9-9c6c-2b869777e64e.png)

Windows 10
1920x1080
Intel i7
for (unsigned int i = 0; i < confTargets.size(); i++) {
        if (confTargets[i] >= target) {
            return i;
        }
    }
    return confTargets.size() - 1;
}
SendCoinsDialog::SendCoinsDialog(const PlatformStyle *_platformStyle, QWidget *parent) :
    QDialog(parent),
    ui(new Ui::SendCoinsDialog),
    clientModel(nullptr),
    model(nullptr),
    fNewRecipientAllowed(true),
    fFeeMinimized(true),
    platformStyle(_platformStyle)
{
    ui->setupUi(this);
    if (!_platformStyle->getImagesOnButtons()) {
        ui->addButton->setIcon(QIcon());
        ui->clearButton->setIcon(QIcon());
        ui->sendButton->setIcon(QIcon());
    } else {
        ui->addButton->setIcon(_platformStyle->SingleColorIcon(":/icons/add"));