Hello!
I just switched to MusicBee as it is a fantastic player. One thing I do miss is being able to drag and drop files from Windows Explorer into MusicBee's queue or using the "Play All" in a folder from the Explorer as well. I am on Windows 10 x64 and I tried both the native explorer and DirectoryOpus.
EDIT: Managed to fix it. Edit -> Preferences, General Tab. Under "file types", I ticked "enable MusicBee in Windows Explorer and Context Menus" and selected all file types, saved and restarted.
Previously I had been unable to open as little as two files at once. Weird.