Hi,
I am Currently using version OpenMPT 1.22.02.00 but I have noticed this problem in older versions. I have added over 100 soundbanks and for some reason, I can drag a lot of them to instrument/Sample window like I can with others, (see Screen1.jpg in zip) :
but I can't seem to drag over some of the soundbank instruments the closer I get to the bottom of the list of the soundbanks I added, but if I delete all I imported and just import the ones I can't drag over, they work fine, but it just seems that after a certain number of soundbanks down the list, it won't let me can drag over any below that point. Any in the red square here are the ones I can't drag over the instruments or can't hear them (I can view them when I click on the folder icon but thats it) (see Screen2.jpg in zip)
Hope I explained this right.
OpenMPT can currently not manage more than 64 soundfonts internally. This limit is not properly enforced when adding new soundfonts, though, so you will have to keep track of it manually. Changing this code to support more soundfonts is complicated, I haven't managed to fix it so far.
Ok, thanks!
I've now finally managed to fix this issue; up to 65536 sound banks can now be loaded: http://sagagames.de/stuff/mptrack.exe