[opensuse-factory] Why did GwenView become the default file manager on my computer?

I notice the issue yesterday when mounting a USB hard-disk with the KDE panel's removable drive icon, and Gwenview launched instead of Dolphin. I have went into KDE settings to switch the default file manager to dolphin to no avail. Restarting again shows that Gwenview is once again selected as the default file manager. How do I force the system into using Dolphin as the default file manager again?