The search view on the project template is still attempting to log queries against the now-removed wagtailsearch.Query model - as of 6.0a0 this is causing an ImportError when running initial migrations on a newly-created project.
Since the wagtail.contrib.search_promotions module is optional (and off by default on new projects), I've opted to comment out the query logging code with instructions for developers who wish to re-enable it.
Ensures that when the iframe content is loaded there is a background on the iframe. So that transparent websites show correctly in the preview panel.
Fixes #11174
