I find that sometimes, if I close the GigaPulse window ... the edit button will not re-open it. The overall interface flashes briefly, as if it is trying to do something with the overall layout ... but GigaPulse fails to appear. It is still there and I can bypass it ... but can't access it.
It seems to happen after the main mixer has been docked (rather than floating). Once it has been docked, and even after removing, GigaPulse is inaccesible via the the edit button.
The only "workaround" is to remove GigaPulse from its effects slot and then re-choose it and manually reset all the parametes. which is not really a workaround.