I want to point out that there is an option for PLAY button that reads "play visible files" that i want it working as it was in versions prior to 10.
When this not work, we are dealing with a workaround, which is not good for a program that surely is the best of its kind.
To be precise: when i want to review some artist or album, I just search for it having the located files in the screen as visible files.
Depending on what i want to do with visible files I select them.
When it comes to play I want to press play button, that not works, so I, not selecting, just click on the first tracks, and that's it. done!
If for some reason i forget the workaround and press PLAY button... the program plays the first track of the library and not the visible file.
Finally i have to say that I've managed my extensive collection with JR Media Jukebox first then with JR Media Center, for years, completely satisfied except for this small issue of PLAY button.