It works only if openMSX is not running yet. This part only requires some meta data in the .app folder. Opening a running instance requires Objective C code, which isn't implemented.
This ticket is for implementing that part, so that opening files with a running instance will be working as well.
File associations on a Mac never work, even when openMSX isn't running yet.
The most annoying missing feature for Mac users....
For me they sometimes work, sometimes not.
I was able to figure out why this is, the files that worked had the extended quarantine attribute (which gets set when you download the file from internets):
When I remove the attribute, double-clicking it stops working:
When I re-add the attribute, double-clicking works again:
Last edit: Laurens Holst 2015-05-02
It does open when the quarantine flag is set? Intuitively, I'd expect the opposite.
Yes, it it surprising to me as well.