Memory Leak in QPlainText

QPlainText does not release memory when removing lines.

This only happens with Qt 5.0.2 and windows (both MSVC and mingw compilers), and does not affect linux.

Example:

    forever{
        ui->plainTextEdit->appendPlainText("DO I LEAK?");
        if(i > 1000){
            ui->plainTextEdit->clear();
            i = 0;
        }
        i++;
    }

When running this example it begin to consume RAM till the end.

If QPlainTextEdit::maximumBlockCount is set behavior is same, lines are removed but memory is not freeing.