I have played a bit with making GRIDTRACK mutes act across page boundaries.
While cool in some cases there are a few issues related to usability.
The most important is that now you have two places on the machine where you control the mutestate inside a page. In the worst case, and not so uncommon, a track will not play and you have to check two places to see if its muted. Not good.
Even if we de-couple the modes in the sense that when in GRIDTRACK the mute patterns of GRIDTRACK are applied, and the "normal" mutepattern is applied for the rest, it is awkward as soon as you have switch out of GRIDTRACK, since your composition changes. Not good either.
Another option could be to make track mutes act on the bank, and not on the page level. But I can see how that can lead to problems as well, although for the moment it seems to be the more harmless of the above.
Let me know your thoughts.