Now most of them just don’t show up at all.
Using Inspect in the Debug menu I can see that they’re claiming to be visible, but they’re not.
I even added a big shape that should just always be visible, but it’s invisible too.
The left half of the screen is the editor. The right half is the live preview. You can see how, at a minimum, Shape L should be visible.
Does Shape L belong to a group? Check in the Elements tree hierarchy, or the parent in the properties page.
Is Shape L “sent to back”? Try “send to front” option.
You can see the hierarchy in the first screen shot. Shape L is in the group that’s visible on both screens (editor and preview).
It looks like the whole group has shrunk to only a few hundred pixels high in the preview, implying that it doesn’t think it has anything inside it taking up space.