Dear XQuartz Developers, I'm teach a class this quarter at Stanford where the main software package we are using is running on Linux (RHEL 6). The application uses Qt5. The students with Windows and Linux laptops are able to view the GUI just fine, but the students with Macs using XQuartz (the majority) are having problems. In particular, when the students try to do a copy, they get the error message QXcbClipboard::setMimeData: Cannot set X11 selection owner and the copy doesn't work. When they quit the application, they get the additional message QApplication::qAppName: Please instantiate the QApplication object first Do any of you have any ideas on how we could fix this? Not being able to copy is a big disadvantage to code development. Many thanks! Bill