Aha ! I knew it!
After I looked in my saved *.med file, while I waited for a fresh pull of master to build so I could prove,
I reasoned away that this section of *.med file might be the
cause and if not certainly needs
attention:
Can you guess why?
Duplicate, blank track names in the song cause that section to screw up and the canvas never is created !
(Notice that each of that drum_ordering entry RELIES on a unique track name, unlike the rest of MusE.)
The new drums and drum ordering were added by Florian.
Possible workarounds for now:
1) After importing your midi tracks, manually rename your tracks ! You will be prompted to choose unique names, fixing the problem.
Sucks, yeah.
2) Remove that section from your *.med file. The file will load. Meh, but then when you save it again the same thing will happen.
Coincidence, I was studying the drum_ordering section just a few days ago, and vowed once and for all to try and optimize it.
That section is
huge! (Also the 200 midi
ports sections - that's my fault.)
Possible fix: It seems obvious to me, and why didn't I see this until now.
Each drum_ordering entry has a 'track' (name)
tying it to a track!
Thus, each of those drum_ordering entries can be
moved right into the track xml entries, found elsewhere, above.
Thus, each track xml entry can then STILL retain its uniqueness even without a unique identifying number or string of any kind
and still be self-contained (as it always has been in MusE), AND have duplicate
blank track names.
However, with that fix out of the way, I would still recommend that some day tracks should get a unique identifier number,
for cases just like this. (Heck, we gave them to Parts and Events, and some other things.)
It's very important also because if track properties and names were to be displayed in a standard list box for example,
we MUST have something uniquely identifying them to tie each list box entry to them.
Note that importing midi files into MusE is the
ONLY case where duplicate track names are allowed. Often they are blank.
This is to preserve the original structure as much as possible (WYSIWYG).
Ye wouldn't want us to auto-name 'em, would ye?