QPlainTextEdit does not respect QTextBlockFormat::lineHeight()

#include "mainwindow.h"
#include <QtWidgets>

int main(int argc, char *argv[])
{
    QApplication a(argc, argv);

    QPlainTextEdit te;
    te.setPlainText("abcabc\ndefdef");

    QTextCursor cursor = te.textCursor();
    cursor.select(QTextCursor::Document);
    QTextBlockFormat fmt;
    fmt.setLineHeight(100, QTextBlockFormat::FixedHeight);
    cursor.setBlockFormat(fmt);

    te.show();

    return a.exec();
}