Hi Francois,
That is indeed the offending piece of code - it's somehow removing the montages we want to use though they make sense for the channels and references. We both tried it on several databases, Matlab and Brainstorm versions. We can see but not select the desired montage using the ALL button, and same for new montages made on the same traces, they are not accessible. I'm afraid we are not coders enough to suggest and debug a better solution - but we do have an ugly work-around (the montage is essential to our sleep scoring). We can comment the lines 1248-1261 in panel_montage. This means all montages appear in the drop-down menu and we can't access the ones we want as they're off the page and it doesn't scroll, but if we make a new one and rename it AAA_..., it appears at the top of the list and can be used for visualization. (I know this will have to be redone each time we update brainstorm, so is not a great solution.)
Best,
Emily