Pages: clicking on page settings before patterns appear causes stacking modals

[annezazu]

Using 6.6.1 and GB 18.8.0, I noticed that when creating a new page I can select items in the sidebar as the patterns modal is loading, causing stacked modals:

parent.page.modal.mov

To replicate:

1. Create a new page.
2. Before the starter patterns appear, select something from the sidebar, like the parent page option.
3. Notice that modals are stacked on top of each other.

In my mind, we just need to change the order so the sidebar options are hidden behind the starter pattern modal. Note that there's anhttps://github.com//pull/61489 around adding zoom out mode with patterns opened in the Inserter instead of starter patterns too which will help here. For now though, this would be helpful to iterate on as is.

[stokesman]

The bug reported here is just a specific instance of #55894

I think what this usefully highlights is why the "Choose a pattern" modal can feel so interruptive and unexpected—its lag. If it could appear before (or at least very nearly at the same time as) the rest of the editor it would be so much less annoying.