fix #3663: 'copying' QR code does not save to file

gui/qt/qrcodewidget.py

@@ -113,8 +113,7 @@ class QRDialog(WindowModalDialog):
 
             def copy_to_clipboard():
                 p = qscreen.grabWindow(qrw.winId())
-                p.save(filename, 'png')
-                QApplication.clipboard().setImage(QImage(filename))
+                QApplication.clipboard().setPixmap(p)
                 self.show_message(_("QR code copied to clipboard"))
 
             b = QPushButton(_("Copy"))