So I was messing around trying to compare a couple of Online Components that were done by the same person, same day, no way to know which was done last to know if there was a correction or something in one of them … and I had my own project open as well so steps are:
Open or create your project
Go to the online components and preview a couple of them at the same time.
Expand the code in both of the online components HTML windows
Flip back and forth between the 2 Online Component Preview HTML windows
They collapse to wherever you manually had it open last. In other words, if you opened part of them and then did the Expand, it will collapse down to your manually opened state.
This is pretty much the only way to check for differences between Online Components that are the same one, but have multiple uploads in the same day.
Just for testing sake, this happens with multiple projects open as well, it’s not just the component previews. If you expand it, it should stay that way until you collapse it yourself.