When using the latest beta (Directory Opus Pro 10.2.0.1), clicking on playlist files and cue sheets opens the file in Notepad++. When opened in Windows Explorer, they behave as they should, i.e. opening and playing in foobar2000. (All files are associated with foobar2000.)
Try right-clicking them and using the Open With menu to change the default program to Foobar2000. That should force them to open in Foobar2000.
The default program is already foobar2000.
Perhaps I should've said more. The default program is already foobar2000, yet they still open in Notepad++.
Did you try what Leo suggested?
Yes, but as foobar2000 is already the default program, it has no effect. That is to say, specifically choosing foobar2000 from the Open With menu works, but closing the program then double-clicking the file opens Notepad++ again.
Did you try Open With -> Choose Default Program?
That will override the existing association via a higher mechanism, so Opus should pick that up even if it is picking up a different default right now.
Just tried, no dice unfortunately.
If you use Open With -> Choose Default Program to move the default for that filetype to another program, does that work?
(If so, try moving it back afterwards, what then?)
If that doesn't work, send me the FileTypeDiag output for the .pls extension and I'll compare it to my own machine.
No,that doesn't work either. Here is the info you requested.
This small registry change should fix things up:
pls_foobar2000.zip (318 Bytes)
That worked a treat Leo, thank you so much 
Just chiming in to say i was having the exact same symptoms.
Leo's reg file did fix it, i wonder if it's DO's "fault" or the OS.
The problem is also happening with .M3U and .CUE playlists btw.
Dang, sorry for filing up this thread (I really miss the EDIT function as long as this is the last message in a thread)
The problem happens on my 32-bit Desktop, but not on my 64bit laptop btw. Perhaps 32bit specific ?
Indeed it is. Which leads me to ask Leo: using the template you gave me, but simply changing to include the .m3u and .cue extensions, would this solve the problem?
I'm on 64-bit, so it appears to be architecture neutral.
The issue in the case I looked at was that there wasn't actually a .pls filetype in the registry, only an Open With override.
The .reg file fixed that by creating a .pls filetype and assigning it the foobar2000.pls ProgID (which was in the registry, just with nothing assigned to it).
Doing similar may fix similar problems too. Depends on exactly what's wrong, of course.
Now that we've seen this, we'll make Opus able to deal with it.
No worries Leo. I'll hold off changing the registry any further. Thanks once again.
I see no reference of this bug in the latest batches for beta's.
Leo, is this problem (bug?) still in the queue to be looked into in the upcoming release(s) ?