Background applications prevent device unmount

Binary package hint: evince

Often, background applications launched by GNOME/Nautilus when accessing a block device remain running in the background even after the user has stopped viewing a directory on the device. This problem is especially noticeable on removable storage such as a USB Flash drive. If the user attempts to eject/unmount the device while one of these background applications is still running, they will be unable to. To unexperienced users, this would be very frustrating as the seems to be no app running still using the device and they can't do anything to make the system allow them to unmount the device. I noticed this problem with evince-thumbnailer which was launched when viewing the root of my USB flash drive but left running indefinitely in the background with a PDF open that apparently evince is incapable of reading(Though Apple Preview can read it). This is obviously a bug in evince-thumbnailer as it doesn't give up. However, this is also a problem for Ubuntu because if a buggy, seemingly hidden, application can lock a device indefinitely then new users will be turned off as they will see it as a problem with the operating system. One possible solution is to kill apps that Nautilus starts on a device if the user is no longer accessing it. Another possible solution is if the user is told the device is still in use upon attempting to unmount it perhaps offer to list the programs still using it and ask the user if they'd like to quit/kill those programs.