This prevents girders from erasing landbacktex (square windows in tunnels and such), at the cost of requiring lfBasic and lfObject to be treated the same apart from graphically
#include <QApplication>
#include "mainform.h"
int main(int argc, char *argv[])
{
QApplication app(argc, argv);
MyWindow *mainWin = new MyWindow;
mainWin->show();
return app.exec();
}