Fixes #5807. If the page instance being previewed gets saved (no confirmation that Wagtail itself is doing this, but it could easily happen as a result of some misplaced logic in get_context or similar), it will block further page creations in a way that's difficult to recover from.
gasman
| Files | Coverage |
|---|---|
| initSkipLink.js | 42.86% |
| initSubmenus.js | 16.67% |
| Folder Totals (2 files) | 26.32% |
| Project Totals (427 files) | 90.05% |