Thanks Matt for your answer.

That would indeed be great but there simply isn't enough storage space available in SCORM 1.2 to have Adapt remember the entire state of the course.

Instead of storing 0 or 1 in the cmi.suspend_data. We could store 0,1 or 2. 2 would means "completed and clicked next". We don't need to use more space.

Maybe we can do this another way : we continue to store 0 or 1 for the completion but we automatically reset the completion of the last completed component. Like that the bookmarked component will match with the first incomplete component and the trickle button will show up. If needed, we can use a global boolean to use this behaviour or not. Otherwise we can change the bookmarked component to the next component so again, the bookmarked component will match with the first incomplete component and no scroll would be needed.

it would be quite annoying for the user to have to click 'Yes' in the bookmarking dialog

Yes ! ...that's why I never use the bookmarking dialog in any course. I always force the bookmark for the user.

then immediately have to click a trickle button to see the next 

Well, in that case, the user has a button to continue at least. When he always click on that button, it is strange to ask him to scroll down himself and he may not even have the idea (it sounds stupid but I have some users like that :D ). Also, graphics and texts components can be "completed" even if the user has not read it, so in that case he doesn't have to click immediately on the trickle button :)