We have UI elements that are dynamically set up as the page is loading.

Historically, we've let these pop in and out of existence during page

load, which doesn't look particularly great. This is very noticeable

with the review banner, and previously the draft banners, which both

show up and set up layout after the content below is shown.
We solved this problem once before for full-viewport pages, like the

dashboard, and are taking basically the same approach now. We now hide

the #page-container element until after we've finished render. The

page header bar will remain visible while the rest of the page loads.
This isn't very noticeable in production, with compiled, cached

JavaScript.
The approach for full-viewport pages used display: block, wheraes now

we use visibility: hidden. This ensures that content can lay out

elements with appropriate bounding boxes, so there aren't any changes in

render or layout.

Tested the dashboard and datagrid pages, review request page, diff

viewer, file attachment review UIs, and administration UI pages.
Checked each type of page for any regressions in appearance.
Verified that this prevents the initial page jump from banners and

suddenly-appearing edit icons for review request fields.