QuickTime Player highjacked MIDI files when I clicked on one to play it from a webpage.It opened a new page with a tiny QuickTime Player in the middle of the GRAY page & played the MIDI.
I didn't think too much of that so I found out how to fix the problem.
See the screenshot below:
I had Windows Media Player set to play MIDIs by default.
But when trying to play them from a webpage QuickTime took over.
WMP would play MIDIs from a MIDI file in My Documents though.
I just had to reset the MIME settings in QuickTime so WMP would play them from the Internet.With WMP you don't lose the page you are on like with QuickTime.